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My ranking of every Shakespeare play

2023-06-22T19:10:25Z

This article was discussed on Hacker News.

A few years ago I set out on a personal journey to study and watch a performance of each of Shakespeare’s 37 plays. I’ve reached my goal and, though it’s not a usual topic around here, I wanted to get my thoughts down while fresh. I absolutely loved some of these plays and performances, and so I’d like to highlight them, especially because my favorites are, with one exception, not “popular” plays. Per tradition, I begin with my least enjoyed plays and work my way up. All performances were either a recording of a live stage or an adaptation, so they’re also available to you if you’re interested, though in most cases not for free. I’ll mention notable performances when applicable. The availability of a great performance certainly influenced my play rankings.

Like many of you, I had assigned reading for several Shakespeare plays in high school. I loathed these assignments. I wasn’t interested at the time, nor was I mature enough to appreciate the writing. Even revisiting as an adult, the conventional selection — Romeo and Juliet, Julius Caesar, etc. — are not highly ranked on my list. For the next couple of decades I thought that Shakespeare just wasn’t for me.

Then I watched the 1993 adaption of Much Ado About Nothing and it instantly became one of my favorite films. Why didn’t we read this in high school?! Reading the play with footnotes helped to follow the humor and allusions. Even with the film’s abridging, some of it still went over my head. I soon discovered Asimov’s Guide to Shakespeare — yes, that Asimov — which was exactly what I needed, and a perfect companion while reading and watching the plays. If stumbling upon this turned out so well, then I’d better keep going.

Wanting a solid set of the plays with good footnotes and editing — there is no canonical version of the plays — I picked up a copy of The Norton Shakespeare. Unfortunately it’s part of the college textbook racket, and it shows. The collection is designed to be sold to students who will lug them in bookbags, will typically open them face-up on a desk, and are uninterested in their contents beyond class. It includes a short-term, digital-only, DRMed component to prevent resale. After all, their target audience will not read it again anyway. Though at least it’s complete and compact, better for reference than reading.

In contrast, the Folger Shakespeare Library mass market paperbacks are better for enthusiasts, both in form and format. They’re clearly built for casual, comfortable reading. However, they’re not sold as a complete set, and gathering used copies takes some work.

Also essential was BBC Television Shakespeare, produced between 1978 and 1985. Finding productions of the more obscure plays is tricky, but it always provided a fallback. In some cases these were the best performances anyway! When I mention “the BBC production” I mean this series. Like many collections, they omit The Two Noble Kinsmen due to unclear authorship, and for this reason I’m omitting it from my list as well. As with any faithful production, I suggest subtitles on the first viewing, as it aids with understanding. Shakespeare’s sentence structure is sometimes difficult to parse by moderns, and on-screen text helps. (By the way, a couple of handy SHA-1 sums for those who know how to use them:)

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As my list will show, my favorites are comedic comedies and histories, particularly the two Henriads, each a group of four plays. The first — Richard II, 1 Henry IV, 2 Henry IV, and Henry V — concerns events around Henry V, in the late 14th and early 15th century. Those number prefixes are parts, as in Henry IV has two parts. In my list I combine parts as though a single play. The second — 1 Henry VI, 2 Henry VI, 3 Henry VI, Richard III — is about the Wars of the Roses, spanning the 15th century. Asimov’s book was essential for filling in the substantial historical background for these plays, and my journey was also in part a history study.

I especially enjoy villain monologues, and plays with them rank higher as a result. It’s said that everyone is the hero of their own story, but Shakespeare’s villains may know that they’re villains and revel it in it, bragging directly to the audience about all the trouble they’re going to cause. In some cases they mock the audience’s sacred values, which in a way, is like the stand up comedy of Shakespeare’s time. Notable examples are Edmund (King Lear), Aaron (Titus Andronicus), Richard III, Iago (Othello), and Shylock (The Merchant of Venice).

As with literature even today, authors are not experts in moral reasoning and protagonists are often, on reflection, incredibly evil. Shakespeare is no different, especially for historical events and people, praising those who create mass misery (e.g. tyrants waging wars) and vilifying those who improve everyone’s lives (e.g. anyone who deals with money). Up to and including Shakespeare’s time, a pre-industrial army on the march was a rolling humanitarian crisis, even in “friendly” territory, slaughtering and stealing its way through the country in order to keep going. So, much like suspension of belief, there’s a suspension of morality where I engage with the material on its own moral terms, however illogical it may be.

Now finally my list. The beginning will be short and negative because, to be frank, I disliked some of the plays. Even Shakespeare had to work under constraints. In his time none were regarded as great works. They weren’t even viewed as literature, but similarly to how we consider television scripts today. Also, around 20% of plays credited to Shakespeare were collaborations of some degree, though the collaboration details have been long lost. For simplicity, I will just refer to the author as Shakespeare.

(37) Timon of Athens

I have nothing positive to say about this play. It’s about a man who borrows and spends recklessly, then learns all the wrong lessons from the predictable results.

(36) The Two Gentlemen of Verona

Involves a couple of love triangles, a woman disguised as a man — a common Shakespeare trope — and perhaps the worst ending to a play ever written. The two “gentlemen” are terrible people and undeserving of their happy ending. Though I enjoyed the scenes with Proteus and Crab, the play’s fool and his dog.

(35) Troilus and Cressida

Interesting that it’s set during the Iliad and features legendary characters such as Achilles, Ajax, and Hector. I have no other positives to note. Cressida’s abrupt change of character in the Greek camp later in the play is baffling, as though part of the play has been lost, and ruins an already dull play for me.

(34) The Winter’s Tale

A baby princess is lost, presumed dead, and raised by shepherds. She is later rediscovered by her father as a young adult. It has a promising start, but in the final act the main plot is hastily resolved off-stage and seemingly replaced with a hastily rewritten ending that nonsensically resolves a secondary story line.

(33) Cymbeline

The title refers to a legendary early King of Britain and is set in the first century, but it is primarily about his daughter. The plot is complicated so I won’t summarize it here. It’s long and I just didn’t enjoy it. This is the second play in the list to feature a woman disguised as a man.

(32) The Tempest

A political exile stranded on an island in the Mediterranean gains magical powers through study, with the help of a spirit creates a tempest that strands his enemies on his island, then gently torments them until he’s satisfied that he’s had his revenge. It’s an okay play.

More interesting is the historical context behind the play. It’s based loosely on events around the founding of Jamestown, Virginia. Until this play, Shakespeare and Jamestown were, in my mind, unrelated historical events. In fact, Pocahontas very nearly met Shakespeare, missing him by just a couple of years, but she did meet his rival, Ben Jonson. I spent far more time catching up on real history, including reading the fascinating True Reportory, than I did on the play.

(31) The Taming of the Shrew

About a man courting and “taming” an ill-tempered woman, the shrew. The seeming moral of the play was outdated even in Shakespeare’s time, and it’s unclear what was intended. Technically it’s a play within a play, and an outer frame presents the play as part of an elaborate prank. However, the outer frame is dropped and never revisited, indicating that perhaps this part of the play was lost. The BBC production skips this framing entirely and plays it straight.

(30) All’s Well That Ends Well

Helena, a low-born enterprising young woman, saves a king’s life. She’s in love with a nobleman, Bertram, and the king orders him to marry her as repayment. He spurns her solely due to her low upbringing and flees the country. She gives chase, and eventually wins him over. Helena is a great character, and Bertram is utterly undeserving of her, which ruins the play for me in an unearned ending.

(29) Antony and Cleopatra

A tragedy about people who we know for sure existed, the first such on the list so far. The sequel to Julius Caesar, completing the story of the Second Triumvirate. Historically interesting, but the title characters were terrible, selfish people, including in the play, and they aren’t interesting enough to make up for it.

I enjoyed the portrayal of Octavian as a shrewd politician.

(28) Julius Caesar

A classic school reading assignment. Caesar’s death in front of the Statue of Pompey is obviously poetic, and so every performance loves playing it up. Antony’s speech is my favorite part of the play. I didn’t dislike this play, but nor did I find it interesting revisiting it as an adult.

(27) Coriolanus

About the career of a legendary Roman general and war hero who attempts to enter politics. He despises the plebeians, which gets him into trouble, but all he really wants is to please is mother. Stratford Festival has a worthy adaption in a contemporary setting.

(26) Henry VIII

He reigned from 1509 to 1547, but the play only covers Henry VIII’s first divorce. It paved the way for the English Reformation, though the play has surprisingly little to say it, or his murder spree. It’s set a few decades after the events of Richard III — too distant to truly connect with the second Henriad.

While I appreciate its historical context — with liberal dramatic license — it’s my least favorite of the English histories. It’s not part of an epic tetralogy, and the subject matter is mundane. My favorite scene is Katherine (Catherine in the history books) firmly rejecting the court’s jurisdiction and walking out. My favorite line: “No man’s pie is freed from his ambitious finger.”

(25) Romeo and Juliet

Another classic reading assignment that requires no description. A beautiful play, but I just don’t connect with its romantic core.

(24) The Merchant of Venice

An infamously antisemitic play where a Jewish moneylender, Shylock, loans to the titular merchant of Venice where the collateral is the original “pound of flesh,” providing the source for that cliche. Though even in his prejudice, Shakespeare can’t help but write multifaceted characters, particularly with Shylock’s famous “If you prick us, do we not bleed?” speech.

(23) Twelfth Night

Twins, a young man and a woman, are separated by a shipwreck. The woman disguises herself as a man and takes employment with a local duke and falls in love with him, but her employment requires her to carry love letters to the duke’s love interest. In the meantime the brother arrives, unaware his sister is in town in disguise, and everyone gets the twins mixed up leading to comedy. It’s a fun play. The title has nothing to do with the play, but refers to the holiday when the play was first performed.

The play is the source of the famous quote, “Some are born great, some achieve greatness, and some have greatness thrust upon them.” It’s used as part of a joke, and when I heard it, I had thought the play was mocking some original source.

(22) Pericles

A Greek play about a royal family — father, mother, daughter — separated by unfortunate — if contrived — circumstances, each thinking the others dead, but all tearfully reunited in a happy ending. My favorite part is the daughter, Marina, talking her way out of trouble: “She’s able to freeze the god Priapus and undo a whole generation.”

The BBC production stirred me, particularly the scene where Pericles and Marina are reunited.

(21) Richard II

Richard II, grandson of the famed Edward III, was a young King of England from 1367 to 1400. At least in the play, he carelessly makes dangerous enemies of his friends, and so is deposed by Henry Bolingbroke, who goes on to become Henry IV. The play is primarily about this abrupt transition of power, and it is the first play of the first Henriad. The conflict in this play creates tensions that will not be resolved until 1485, the end of the Wars of the Roses. Shakespeare spends seven additional plays on this a huge, interesting subject.

For me, Richard II is the most dull of the Henriad plays. It’s a slow start, but establishes the groundwork for the greater plays that follow. The BBC production of the first Henriad has “linked” casting where the same actors play the same roles through the four plays, which makes this an even more important watch.

(20) Othello

Another of the famous tragedy. Othello, an important Venetian general, and “the Moore of Venice” is dispatched to Venice-controlled Cyprus to defend against an attack by the Ottoman Turks. Iago, who has been overlooked for promotion by Othello, treacherously seeks revenge, secretly sabotaging all involved while they call him “honest Iago.” Though his schemes quickly go well beyond revenge, and continues sowing chaos just for his own fun.

I watched a few adaptions, and I most enjoyed the 2015 Royal Shakespeare Company Othello, which places it in a modern setting and requires few changes to do so.

(19) The Comedy of Errors

A fun, short play about a highly contrived situation: Two pairs of twins, where each pair of brothers has been given the same name, is separated at birth. As adults they all end up in the same town, and everyone mixes them up leading to comedy. It’s the lightest of Shakespeare’s plays, but also lacks depth.

(18) Hamlet

Another common, more senior, high school reading assignment. Shakespeare’s longest play, and probably the most subtle. In everything spoken between Hamlet and his murderous uncle, Claudius, one must read between the lines. Their real meanings are obscured by courtly language — familiar to Shakespeare’s audience, but not moderns. Asimov is great for understanding the political maneuvering, which is a lot like a game of chess. It made me appreciate the play more than I would have otherwise.

You’d be hard-pressed to find something that beats the faithful, star-studded 1996 major film adaption.

(17) Richard III

The final play of the second Henriad. Much of the play is Richard III winking at the audience, monologuing about his villainous plans, then executing those plans without remorse. Makes cheering for the bad guy fun. If you want to see an evil schemer get away with it, at least right up until the end when he gets his comeuppance, this is the play for you. This play is the source of the famous “My kingdom for a horse.”

I liked two different performances for different reasons. The 1995 major film puts the play in the World Word II era. It’s solid and does well standing alone. The BBC production has linked casting with the three parts of Henry VI, which allows one to enjoy it in full in its broader context. It’s also well-performed, but obviously has less spectacle and a lower budget.

(16) The Merry Wives of Windsor

The comedy spin-off of Henry IV. Allegedly, Elizabeth I liked the character of John Falstaff from Henry IV so much — I can’t blame her! — that she demanded another play with the character, and so Shakespeare wrote this play. The play brings over several characters from Henry IV. Unfortunately it’s in name only and they hardly behave like the same characters. Despite this, it’s still fun and does not require knowledge of Henry IV.

Falstaff ineptly attempts to seduce two married women, the titular wives, who play along in order to get revenge on him. However, their husbands are not in on the prank. One suspects infidelity and hatches his own plans. The confusion leads to the comedy.

The 2018 Royal Shakespeare Company production aptly puts it in a modern suburban setting.

(15) Titus Andronicus

A play about a legendary Roman general committed to duty above all else, even the lives of his own sons. He and his family become brutal victims of political rivals, and in return gets his own brutal revenge. It’s by far Shakespeare’s most violent and disturbing play. It’s a bit too violent even for me, but it ranks this highly because Aaron the Moore is such a fantastic character, another villain that loves winking at the audience. His lines throughout the play make me smile: “If one good deed in all my life I did, I do repent it from my very soul.”

I enjoyed the 1999 major film, which puts it in a contemporary setting.

(14) King Lear

The titular, mythological king of pre-Roman Britain wants to retire, and so he divides his kingdom between his three daughters. However, after petty selfishness on Lear’s part, he disowns the most deserving daughter, while the other two scheme against one another.

Some of the scenes in this play are my favorite among Shakespeare, such as Edmund’s monologue on bastards where he criticizes the status quo and mocks the audience’s beliefs. It also has one of the best fools, who while playing dumb, is both observant and wise. That’s most of Shakespeare’s fools, but it’s especially true in King Lear (“This is not altogether fool, my lord.”). This fool uses this “tenure” to openly mock the king to his face, the only character that can do so without repercussions.

My favorite performance was the 2015 Stratford Festival stage production, especially for its Edmund, Lear, and Fool.

(13) Macbeth

The shortest tragedy, a common reading assignment, and a perfect example of literature I could not appreciate without more maturity. Even the plays I dislike have beautiful poetry, but I especially love it in Macbeth.

The history behind Macbeth is itself fascinating. The play was written custom for the newly-crowned King James I — of King James Version fame — and even calls him out in the audience. James I was obsessed with witch hunts, so the play includes witchcraft. The character Banquo was by tradition considered to be his ancestor.

My favorite production by far — I watched a number of them! — was the 2021 film. It should be an approachable introduction for Shakespeare newcomers more interested in drama than comedy. Notably for me, it departs from typical productions in that Macbeth and Lady Macbeth do not scream at each other — perhaps normally a side effect of speaking loudly for stage performance. Particularly in Act 1, Scene 7 (“screw your courage to the sticking place”). In the film they argue calmly, like a couple in a genuine, healthy relationship, making the tragedy that much more tragic.

That being said, it drops the ball with the porter scene — a bit of comic relief just after Macbeth murders Duncan. There’s knocking at the gate, and the porter, charged with attending it, is hungover and takes his time. In a monologue he imagines himself porter to Hell, and on each impatient knock considers the different souls he would be greeting. Of all the porter scenes I watched, the best porter as the 2017 Stratford Festival production, where he is both charismatic and hilarious. I wish I could share a clip.

(12) King John

King John, brother of “Coeur de Lion” Richard I, ruled in early 13th century. His reign led to the Magna Carta, and he’s also the Prince John of the Robin Hood legend, though because it’s a history, and paints John in a positive light, that legend isn’t included. It depicts fascinating, real historical events and people, including Eleanor of Aquitaine. It also has one of my favorite Shakespeare characters, Phillip the Bastard, who gets all the coolest lines. I especially love his introductory scene where his lineage is disputed by his half-bother and Eleanor, impressed, essentially adopts him on the spot.

The 2015 Stratford Festival stage performance is wonderful, and I’ve re-watched it a few times. The performances are all great.

(11–9) Henry VI

As previously noted, this is actually three plays. At 3–4 hours apiece, it’s about the length of a modern television season. I thought it might take awhile to consume, but I was completely sucked in, watching and studying the whole trilogy in a single weekend.

Henry V died young in 1422, and his infant son became Henry VI, leaving England ruled by his uncles. As an adult he was a weak king, which allowed the conflicts of the previously-mentioned Richard II to bubble up into the Wars of the Roses, a bloody power conflict between the Lancasters and Yorks. The play features historical people including Joan la Pucelle (“Joan of Arc”), English war hero John Talbot, and Jack Cade. Richard III wraps up the conflicts of Henry VI, forming the second Henriad. When watching/reading the play, keep in mind that the play is anti-French, anti-York, and (implicitly) pro-Tudor.

Most of the first part was probably not written by Shakespeare, but rather adapted from an existing play to fill out the backstory. I think I can see the “seams” between the original and the edits that introduce the roses.

I loved the BBC production of the second Henriad. Producing such an epic story must be daunting, and it’s amazing what they could convey with such limited budget and means. It has hilarious and clever cinematography for the scene where the Countess of Auvergne attempts to trap Talbot (Part 1, Act 2, Scene 3). Again, I wish I could share a clip!

(8) Henry V

Due to his amazing victories, most notably at Agincourt where, for once, Shakespeare isn’t exaggerating the odds, Henry V is one of the great kings of English history. This play is a followup to Richard II and Henry IV, completing the first Henriad, and depicts Henry V’s war with France. Outside of the classroom, this is one of Shakespeare’s most popular plays.

The obvious choice for viewing is the 1989 major film, which, by borrowing a few scenes from Henry IV, attempts a standalone experience, though with limited success. I watched it before Henry IV, and I could not understand why the film was so sentimental about a character that hadn’t even appeared yet. It probably has the best Saint Crispin’s Day Speech ever performed, in part because it’s placed in a broader context than originally intended. The introduction is bold as is Exeter’s ultimatum delivery. It cleverly, and without changing his lines, also depicts Montjoy, the French messenger, as sympathetic to the English, also not originally intended. I didn’t realize this until I watched other productions.

The BBC production is also worthy, in large part because of its linked casting with Richard II and Henry IV. It’s also unabridged, including the whole glove thing, for better or worse.

(7–6) Henry IV

People will think I’m crazy, but yes, I’m placing Henry IV above Henry V. My reason is just two words: John Falstaff. This character is one of Shakespeare’s greatest creations, and really makes these plays for me. As previously noted, this is two plays mainly because John Falstaff was such a huge hit. The sequel mostly retreads the same ground, but that’s fine! I’ve read and re-read all the Falstaff scenes because they’re so fun. I now have a habit of quoting Falstaff, and it drives my wife nuts.

The Falstaff role makes or breaks a Henry IV production, and my love for this play is in large part thanks to the phenomenal BBC production. It has a warm, charismatic Falstaff that perfectly nails the role. It’s great even beyond Falstaff, of course. At the end of part 2, I tear up seeing Henry V test the chief justice. I adore this production. What a masterpiece.

(5) A Midsummer Night’s Dream

A popular, fun, frivolous play that I enjoyed even more than I expected, where faeries interfere with Athenians who wander into their forest. The “rude mechanicals” are charming, especially the naive earnestness of Nick Bottom, making them my favorite part of the play.

My enjoyment is largely thanks to a 2014 stage production with great performances all around, great cinematography, and incredible effects. Highly recommended. Honorable mention goes to the great Nick Bottom performances of the BBC production and the 1999 major film.

(4) As You Like It

A pastoral comedy about idyllic rural life, and the source of the famous quote “All the world’s a stage.” A duke has deposed his duke brother, exiling him and his followers to the forest where the rest of the play takes place. The main character, Rosalind, is one of the exiles, and, disguised as a man named Ganymede, flees into the forest with her cousin. There she runs into her also-exiled love interest, Orlando. While still disguised as Ganymede, she roleplays as Rosalind — that is, herself — to help him practice wooing herself. Crazy and fun.

A couple of my favorite lines are “There’s no clock in the forest” and “falser than vows made in wine.” It’s an unusually musical play, and has a big, happy ending. The fool, Touchstone, is one of my favorite fools, named such because he tests the character of everyone with whom he comes in contact.

It ranks so highly because of an endearing 2019 production by Kentucky Shakespeare, which sets the story in a 19th century Kentucky. This is the most amateur production I’ve shared so far — literally Shakespeare in the park — but it’s just so enjoyable. Their Rosalind is fantastic and really makes the play work. I’ve listened to just the audio of the play, like a podcast, many times now.

(3) Measure for Measure

A comedy about justice and mercy. The duke of Vienna announces he will be away on a trip to Poland, but secretly poses as a monk in order to get his thumb on the pulse of his city. Unfortunately the man running the city in his stead is corrupt, and the softhearted duke can’t help but pull strings behind the scenes to undo the damage, and more. He sets up a scheme such that, after his dramatic return as duke, the plot is unraveled while simultaneously testing the character of all involved.

I love so many of the characters and elements of this play. I smile when the duke jumps into action, my heart wrenches at Isabella’s impassioned speech for mercy (“it is excellent to have a giant’s strength, but it is tyrannous to use it like a giant”), I admire the provost’s selfless loyalty to the duke, I laugh when Lucio the “fantastic” keeps putting his foot in his mouth, and I cry when Mariana begs Isabella to forgive. All around a wonderful play.

Like so many already, a big part of my love for the play is the BBC production, which is full of great performances, particularly the duke, Isabella, and Lucio.

(2) Much Ado About Nothing

As the play that finally got me interested in Shakespeare, of course it’s near the top of the list. Forget Romeo and Juliet: Benedick and Beatrice are Shakespeare’s greatest romantic pairing!

Don Pedro, Prince of Aragon, stops in Messina with his soldiers while returning from a military action. While in town there’s a matchmaking plot and lots of eavesdropping, and then chaos created by the wicked Don John, brother to Don Pedro. It’s a fun, light, hilarious play. It also features another of Shakespeare’s great comic characters, Dogberry, famous for his malapropisms.

This is a very popular play with tons of productions, though I only watched a few of them. The previously-mentioned 1993 adaption remains my favorite. It does some abridging, but honestly, it makes the play better and improves the comedic beats.

(1) Love’s Labour’s Lost

Finally, my favorite play of all, and an unusual one to be at the top of the list. Much of the play is subtle parody and so makes for a poor first play for newcomers, who would not be familiar enough with Shakespeare’s language to distinguish parody from genuine.

The King of Navarre and three lords swear an oath to seclude themselves in study, swearing off the company of women. Then the French princess and her court arrives, the four men secretly write love letters in violation of their oaths, and comedy ensues. There are also various eccentric side characters mixed into the plot to spice it up. It’s all a ton of fun and ends with an inept play within a play about the “nine worthies.”

The major reason I love this play so much is a literally perfect 2017 production by Stratford Festival. I love every aspect of this production such that I can’t even pick a favorite element. I was hooked within the first minute.

The Missing Computer Skills of High School Students

2018-10-31T22:02:36Z

This article was discussed on Hacker News and discussed on Reddit.

It’s been just over fours years since I started mentoring high school students at work, and I recently began mentoring my fourth such student. That’s enough students for me to start observing patterns. Of course, each arrives with different computer knowledge and experience, but there have been two consistent and alarming gaps. One is a concept and the other is a skill, both of which I expect an advanced high schooler, especially one interested in computers, to have before they arrive. This gap persists despite students taking computer classes at school.

File, Directories, and Paths

The vital gap in concepts is files, directories, or, broadly speaking, paths. Students do initially arrive with a basic notion of files and directories (i.e. “folders”) and maybe some rough idea that there’s a hierarchy to it all. But they’ve never learned the notation: a location to a file specified by a sequence of directory components which may be either relative or absolute. More specifically, they’ve never been exposed to the concepts of . (current directory) nor .. (parent directory).

The first thing I do with my students is walk them though a Linux installation process and then sit them in front of a terminal. Since most non-option arguments are file paths, shell commands are rather limited if you don’t know anything about paths. You can’t navigate between directories or talk about files outside of your home directory. So one of the first things I have to teach is how paths work. We go through exercises constructing and reasoning about paths, and it takes some time and practice for students to really “get” them.

And this takes longer than you might think! Even once the student has learned the basic concepts, it still takes practice to internalize and reason about them. It’s been a consistent enough issue that I really should assemble a booklet to cover it, and perhaps some sort of interactive practice. I could just hand this to the student so they can learn on their own as they do with other materials.

Paths aren’t just imporant for command line use. They come up in every day programming when programs need to access files. In some contexts it even has security implications regardless of the programming language. For example, care must be taken handling and validating paths supplied from an untrusted source. A web application may need to translate a path-like string in a query into a file path, and not understanding how .. works can make this dangerous. Or not understanding how paths need to be normalized before being compared.

I consider paths as falling under file and directory basics, and it’s part of the baseline for a person to be considered computer literate.

Touch Typing

The other major gap is touch typing. None of my students have been touch typists, and it slows them all down far more than they realize. I spend a lot of time next to them at the keyboard as they drive, so I’ve seen the costs myself. In a couple of cases, the students have to finger peck while looking at the keyboard.

An important step in mastering the use of computers is quickly iterating on new ideas and concepts — trying out and playing with things as they are learned. Being a slow typist not only retards this process, the tedium of poor, plodding keyboarding actively discourages experimentation, becoming a barrier. Advanced computer use isn’t much fun if you can’t type well.

To be fair, I’ve only been a proper touch typist for under two years. I wish I had learned it much earlier in life, and I really only have myself to blame that it took so long. Fortunately I had developed my own pseudo touch touching style that required neither finger pecking nor looking at the keyboard. My main issue was accuracy, not that typing was tedious or slow.

The bad news is that, unlike paths, this is completely outside my control. First, one of the major guidelines of the mentoring program is that we’re not supposed to spend a lot of time on basic skills. Learning to touch type takes several weeks of daily effort. That’s just too much time that we don’t have. Second, this won’t work anyway unless the student is motivated to learn it. I have no idea how to provide that sort of motivation. (And if the student is motivated, they’ll do it on their own time anyway.) I think that’s where schools get stuck.

The really bad news is that this problem is going to get worse. The mobile revolution happened, and, for most people, mobile devices are gradually replacing the home computer, even laptops. I already know one student who doesn’t have access to a general purpose computer at home. The big difference between a tablet and a laptop is that a tablet is purely for consumption.

In the future, kids will be less and less exposed to keyboards, and productive computing in general. Keyboards are, and will continue to be for the foreseeable future, a vital tool for professionals. I wonder if the future will be a bit like, say, the 1980s again, where only a small fraction of kids will be exposed to a proper computer. Only instead of a PC clone, Commodore, or Apple II, it’s a Raspberry Pi.

Conclusions

I want to make something really clear: I’m not blaming the students for these gaps. It’s not in any way their fault. What they’re taught and exposed to is, at this point in life, largely outside of their control.

I lay most of the blame on the schools. My mentees have all taken high school programming classes of some sort, but these classes somehow manage to skip over the fundamentals. Instead it’s rote learning some particular IDE without real understanding. Finally I can relate to all those mathematicians’ complaining about how math class is taught!

What can be done? If you’re a parent, make sure your kid has access to a general purpose computer, even if it’s only a Raspberry Pi or one of its clones, along with a keyboard and mouse. (Of course, if you’re reading this article you’re not one of the parents that needs this advice.) It’s good exposure all around.

After reflecting on this recently, I think one of the shortcomings of my mentoring is that I don’t spend enough time — generally none at all — at the keyboard driving with my mentee as the passenger, where they can really observe me in action. Usually it’s me approaching them to check on their progress, and the opportunity just isn’t there. Perhaps it would be motivating to see how efficient and fun computing can be at higher levels of proficiency — to show them how touch typing and a powerful text editor can lead to such a dramatic difference in experience. It would be the answer to that question of, “Why should I learn this?”

Introducing the Pokerware Secure Passphrase Generator

2017-07-27T17:49:10Z

I recently developed Pokerware, an offline passphrase generator that operates in the same spirit as Diceware. The primary difference is that it uses a shuffled deck of playing cards as its entropy source rather than dice. Draw some cards and use them to select a uniformly random word from a list. Unless you’re some sort of tabletop gaming nerd, a deck of cards is more readily available than five 6-sided dice, which would typically need to be borrowed from the Monopoly board collecting dust on the shelf, then rolled two at a time.

There are various flavors of two different word lists here:

https://github.com/skeeto/pokerware/releases/tag/1.0

Hardware random number generators are difficult to verify and may not actually be as random as they promise, either intentionally or unintentionally. For the particularly paranoid, Diceware and Pokerware are an easily verifiable alternative for generating secure passphrases for cryptographic purposes. At any time, a deck of 52 playing cards is in one of 52! possible arrangements. That’s more than 225 bits of entropy. If you give your deck a thorough shuffle, it will be in an arrangement that has never been seen before and will never be seen again. Pokerware draws on some of these bits to generate passphrases.

The Pokerware list has 5,304 words (12.4 bits per word), compared to Diceware’s 7,776 words (12.9 bits per word). My goal was to invent a card-drawing scheme that would uniformly select from a list in the same sized ballpark as Diceware. Much smaller and you’d have to memorize more words for the same passphrase strength. Much larger and the words on the list would be more difficult to memorize, since the list would contain longer and less frequently used words. Diceware strikes a nice balance at five dice.

One important difference for me is that I like my Pokerware word lists a lot more than the two official Diceware lists. My lists only have simple, easy-to-remember words (for American English speakers, at least), without any numbers or other short non-words. Pokerware has two official lists, “formal” and “slang,” since my early testers couldn’t agree on which was better. Rather than make a difficult decision, I took the usual route of making no decision at all.

The “formal” list is derived in part from Google’s Ngram Viewer, with my own additional filters and tweaking. It’s called “formal” because the ngrams come from formal publications and represent more formal kinds of speech.

The “slang” list is derived from every reddit comment between December 2005 and May 2017, tamed by the same additional filters. I have this data on hand, so I may as well put it to use. I figured more casually-used words would be easier to remember. Due to my extra filtering, there’s actually a lot of overlap between these lists, so the differences aren’t too significant.

If you have your own word list, perhaps in a different language, you can use the Makefile in the repository to build your own Pokerware lookup table, both plain text and PDF. The PDF is generated using Groff macros.

Passphrase generation instructions

Thoroughly shuffle the deck.
Draw two cards. Sort them by value, then suit. Suits are in alphabetical order: Clubs, Diamonds, Hearts, Spades.
Draw additional cards until you get a card that doesn’t match the face value of either of your initial two cards. Observe its suit.
Using your two cards and observed suit, look up a word in the table.
Place all cards back in the deck, shuffle, and repeat from step 2 until you have the desired number of words. Each word is worth 12.4 bits of entropy.

A word of warning about step 4: If you use software to do the word list lookup, beware that it might save your search/command history — and therefore your passphrase — to a file. For example, the less pager will store search history in ~/.lesshst. It’s easy to prevent that one:

$ LESSHISTFILE=- less pokerware-slang.txt

Example word generation

Suppose in step 2 you draw King of Hearts (KH/K♥) and Queen of Clubs (QC/Q♣).

In step 3 you first draw King of Diamonds (KD/K♦), discarding it because it matches the face value of one of your cards from step 2.

Next you draw Four of Spades (4S/4♠), taking spades as your extra suit.

In order, this gives you Queen of Clubs, King of Hearts, and Spades: QCKHS or Q♣K♥♠. This corresponds to “wizard” in the formal word list and would be the first word in your passphrase.

A deck of cards as an office tool

I now have an excuse to keep a deck of cards out on my desk at work. I’ve been using Diceware — or something approximating it since I’m not so paranoid about hardware RNGs. From now I’ll deal new passwords from an in-reach deck of cards. Though typically I need to tweak the results to meet outdated character-composition requirements.

My Journey with Touch Typing and Vim

2017-04-01T04:02:08Z

Given the title, the publication date of this article is probably really confusing. This was deliberate.

Three weeks ago I made a conscious decision to improve my typing habits. You see, I had a dirty habit. Despite spending literally decades typing on a daily basis, I’ve been a weak typist. It wasn’t exactly finger pecking, nor did it require looking down at the keyboard as I typed, but rather a six-finger dance I developed organically over the years. My technique was optimized towards Emacs’ frequent use of CTRL and ALT combinations, avoiding most of the hand scrunching. It was fast enough to keep up with my thinking most of the time, but was ultimately limiting due to its poor accuracy. I was hitting the wrong keys far too often.

My prime motivation was to learn Vim — or, more specifically, to learn modal editing. Lots of people swear by it, including people whose opinions I hold in high regard. The modal editing community is without a doubt larger than the Emacs community, especially since, thanks to Viper and Evil, a subset of the Emacs community is also part of the modal editing community. There’s obviously something significantly valuable about it, and I wanted to understand what that was.

But I was a lousy typist who couldn’t hit the right keys often enough to make effective use of modal editing. I would need to learn touch typing first.

Touch typing

How would I learn? Well, the first search result for “online touch typing course” was Typing Club, so that’s what I went with. By the way, here’s my official review: “Good enough not to bother checking out the competition.” For a website it’s pretty much the ultimate compliment, but it’s not exactly the sort of thing you’d want to hear from your long-term partner.

My hard rule was that I would immediately abandon my old habits cold turkey. Poor typing is a bad habit just like smoking, minus the cancer and weakened sense of smell. It was vital that I unlearn all that old muscle memory. That included not just my six-finger dance, but also my NetHack muscle memory. NetHack uses “hjkl” for navigation just like Vim. The problem was that I’d spent a couple hundred hours in NetHack over the past decade with my index finger on “h”, not the proper home row location. It was disorienting to navigate around Vim initally, like riding a bicycle with inverted controls.

Based on reading other people’s accounts, I determined I’d need several days of introductory practice where I’d be utterly unproductive. I took a three-day weekend, starting my touch typing lessons on a Thursday evening. Boy, they weren’t kidding about it being slow going. It was a rough weekend. When checking in on my practice, my wife literally said she pitied me. Ouch.

By Monday I was at a level resembling a very slow touch typist. For the rest of the first week I followed all the lessons up through the number keys, never progressing past an exercise until I had exceeded the target speed with at least 90% accuracy. This was now enough to get me back on my feet for programming at a glacial, frustrating pace. Programming involves a lot more numbers and symbols than other kinds of typing, making that top row so important. For a programmer, it would probably be better for these lessons to be earlier in the series.

For that first week I mostly used Emacs while I was finding my feet (or finding my fingers?). That’s when I experienced first hand what all these non-Emacs people — people who I, until recently, considered to be unenlightened simpletons — had been complaining about all these years: Pressing CTRL and ALT key combinations from the home row is a real pain in in the ass! These complaints were suddenly making sense. I was already seeing the value of modal editing before I even started really learning Vim. It made me look forward to it even more.

During the second week of touch typing I went though Derek Wyatt’s Vim videos and learned my way around the :help system enough to bootstrap my Vim education. I then read through the user manual, practicing along the way. I’ll definitely have to pass through it a few more times to pick up all sorts of things that didn’t stick. This is one way that Emacs and Vim are a lot alike.

Update: Practical Vim: Edit Text at the Speed of Thought was recommended in the comments, and it’s certainly a better place to start than the Vim user manual. Unlike the manual, it’s opinionated and focuses on good habits, which is exactly what a newbie needs.

One of my rules when learning Vim was to resist the urge to remap keys. I’ve done it a lot with Emacs: “Hmm, that’s not very convenient. I’ll change it.” It means my Emacs configuration is fairly non-standard, and using Emacs without my configuration is like using an unfamiliar editor. This is both good and bad. The good is that I’ve truly changed Emacs to be my editor, suited just for me. The bad is that I’m extremely dependent on my configuration. What if there was a text editing emergency?

With Vim as a sort of secondary editor, I want to be able to fire it up unconfigured and continue to be nearly as productive. A pile of remappings would prohibit this. In my mind this is like a form of emergency preparedness. Other people stock up food and supplies. I’m preparing myself to sit at a strange machine without any of my configuration so that I can start the rewrite of the software lost in the disaster, so long as that machine has vi, cc, and make. If I can’t code in C, then what’s the point in surviving anyway?

The other reason is that I’m just learning. A different mapping might seem more appropriate, but what do I know at this point? It’s better to follow the beaten path at first, lest I form a bunch of bad habits again. Trust in the knowledge of the ancients.

Future directions

I am absolutely sticking with modal editing for the long term. I’m really enjoying it so far. At three weeks of touch typing and two weeks of modal editing, I’m around 80% caught back up with my old productivity speed, but this time I’ve got a lot more potential for improvement.

For now, Vim will continue taking over more and more of my text editing work. My last three articles were written in Vim. It’s really important to keep building proficiency. I still rely on Emacs for email and for syndication feeds, and that’s not changing any time soon. I also really like Magit as a Git interface. Plus I don’t want to abandon years of accumulated knowledge and leave the users of my various Emacs packages out to dry. Ultimately I believe will end up using Evil, to get what seems to be the best of both worlds: modal editing and Emacs’ rich extensibility.

Two Years as a High School Mentor

2016-09-02T21:37:51Z

Update June 2019: Dan graduated from college and is now my full-time colleague.

Over the past two years I’ve been mentoring a high school student, Dan Kelly, in software development though my workplace mentoring program. It’s been one of the most rewarding experiences in my life, far beyond my initial expectations. It didn’t just go well, it went extraordinarily well. One of my co-workers described the results as, “the single most successful technical investment I’ve ever seen made in a person.” Last week the mentorship effectively ended as he became a college freshman. While it’s fresh in my mind, I’d like to reflect on how it went and why this arrangement worked so particularly well for both of us.

Students come into work for a few hours at a time a few days each week throughout the school year, typically after school. They’re supplied with their own computer in a mentor-arranged work space. In my case, Dan sat at a smaller makeshift desk in my office. The schedule is informal and we were frequently making adjustments as needed.

An indispensable feature is that the students are unpaid. Based on my observations, the primary reason many other mentorships aren’t nearly as effective is a failure to correctly leverage this. Some mentors put students directly to work on an existing, funded project. This is a mistake. Real world, practical projects are poor learning environments for beginners. The complexity inhibits development of the fundamentals, and, from a position of no experience, the student will have little ability to influence the project, stifling their motivation.

If being unpaid sounds unfair, remember that these students are coming in with essentially no programming experience. For several months, students are time sink. Maybe they fiddled around with Python on their own, but it probably doesn’t really amount to anything meaningful (yet).

Being unpaid means students can be put to work on anything, even if unfunded — even if it’s only for the student’s own benefit. The very first thing I did with Dan was to walk him through an install of Debian (wiping the near-useless, corporate Windows image). I wanted him fully in control of, and responsible for, his own development environment. I never sat at his keyboard, and all exercises took place at his computer.

From here I took a bit of an unconventional approach: I decided he was going to learn from the bottom up, starting with C. There would be no Fisher-Price-esque graphical programming language (yes, some mentors actually do this), not even an easier, education-friendly, but production-ready language like Python. I wanted him to internalize pointers before trusting him with real work. I showed him how to invoke gcc, the various types of files involved, how to invoke the linker, and lent him my hard copy of first edition K&R.

Similarly, I wasn’t going to start him off with some toy text editor. Like with C, he was going to learn real production tools from the start. I gave the Emacs run-down and started him on the tutorial (C-h t). If he changed his mind later after getting more experience, wanting to use something different, that would be fine.

Once he got the hang of everything so far, I taught him Git and Magit. Finally we could collaborate.

The first three months were spent on small exercises. He’d learn a little bit from K&R, describe to me what he learned, and I’d come up with related exercises, not unlike those on DailyProgrammer, to cement the concepts. I’d also translate concepts into modern C (e.g. C99).

With K&R complete, he was ready to go beyond simple exercises. Unfortunately, I wasn’t able to involve him in my own work at the time. His primary interests included graphics, so we decided on a multi-threaded, networked multi-processor raytracer.

It was a lot more educational for us both than I expected. I spent a significant amount of personal time learning graphics well enough to keep ahead: color spaces, blending, anti-aliasing, brushing up on linear algebra, optics, lighting models, modeling formats, Blender, etc. In a few cases I simply learned it from him. It reminds me of a passage from The Moon is a Harsh Mistress (the namesake of this blog):

I liked Prof. He would teach anything. Wouldn’t matter that he knew nothing about it; if pupil wanted it, he would smile and set a price, locate materials, stay a few lessons ahead. Or barely even if he found it tough—never pretended to know more than he did. Took algebra from him and by time we reached cubics I corrected his probs as often as he did mine—but he charged into each lesson gaily.

I started electronics under him, soon was teaching him. So he stopped charging and we went along together until he dug up an engineer willing to daylight for extra money—whereupon we both paid new teacher and Prof tried to stick with me, thumb-fingered and slow, but happy to be stretching his mind.

Since this was first and foremost an educational project, I decided we would use no libraries other than the (POSIX) C standard library. He would know how nearly every aspect of the program worked. The input (textures) and output formats were Netpbm PPMs, BMP files, and YUV4MPEG2 (video), each of which is very easy to read and write. It loaded 3D models in the easy-to-parse Wavefront .obj format. It also supported a text rendered overlay, initially using our own font format and later with fonts in the Glyph Bitmap Distribution Format — again, easy to parse and use. The text made it possible to produce demo videos without any additional editing (see the above video).

After a year on the raytracer, he had implemented most of what he wanted and I had an opportunity to involve him in my funded research. By this point he was very capable, quickly paying back his entire education.

Together we made rapid progress — much more than I could alone. I can’t go into the specifics, but much of his work was built on lessons learned from the raytracer, including an OpenGL display and SIMD-optimized physics engine. I also taught him x86 assembly, which he applied to co-author a paper, ROP Gadget Prevalence and Survival under Compiler-based Binary Diversification Schemes (slides).

To reiterate, an important part of this entire journey was the influence he had over his own work. He had say on the direction of each project. Until he started earning a college intern pay (post-graduation), I had no ability to make him do anything he didn’t want to do. I could only rely on his motivation. Fortunately what motivates him is what also motivates me, so to find the framing for that motivation I only had to imagine myself in his shoes.

A Comment on Respect

An important aspect I hadn’t noticed until the second year was respect. Most of Dan’s interactions with other co-workers was very respectful. They listened to what he had to say and treated it with the same respect as they would a regular, full-time co-worker. I can’t emphasize how invaluable this is for a student.

I bring this up because there were a handful of interactions that weren’t so respectful. A few individuals, when discovering his status, made a jokes (“Hey, where’s my coffee?”) or wouldn’t take his comments seriously. Please don’t be one of these people.

What’s comes next?

In many ways, Dan is starting college in a stronger position than I was finishing college. The mentorship was a ton of vocational, practical experience that doesn’t normally happen in a college course. However, there’s plenty of computer science theory that I’m not so great at teaching. For example, he got hands on experience with practical data structures, but only picked up a shallow understanding of their analysis (Big O, etc.). College courses will fill those gaps, and they will be learned more easily with a thorough intuition of their context.

As he moves on, I’ll be starting all over again with a new student.

Digispark and Debian

2014-05-14T17:57:31Z

Following Brian’s lead, I recently picked up a couple of Digispark USB development boards. It’s a cheap, tiny, Arduino-like microcontroller. There are a couple of interesting project ideas that I have in mind for these. It’s been over 6 years since I last hacked on a microcontroller.

Unfortunately, support for the Digispark on Linux is spotty. Just as with any hardware project, the details are irreversibly messy. It can’t make use of the standard Arduino software for programming the board, so you have to download a customized toolchain. This download includes files that have the incorrect vendor ID, requiring a manual fix. Worse, the fix listed in their documentation is incomplete, at least for Debian and Debian-derived systems.

The main problem is that Linux will not automatically create a /dev/ttyACM0 device like it normally does for Arduino devices. Instead it gets a long, hidden, unpredictable device name. The fix is to ask udev to give it a predictable name by appending the following to the first line in the provided udev rules file (49-micronucleus.rules),

SYMLINK+="ttyACM%n"

The whole uncommented portion of the rules file should look like this:

49-micronucleus.rules (pastebin since it’s a long line)

The == is a conditional operator, indicating that the rule only applies when the condition is met. The := and += are assignment operators, evaluated when all of the conditions are met. The SYMLINK part tells udev put a softlink to the device in /dev under a predictable name.

Emacs, Thanksgiving, and Hanukkah

2013-11-28T22:25:36Z

Today is Thanksgiving in the United States. It also happens to be Hanukkah. There’s been news going around that Thanksgiving and Hanukkah will not coincide again for about 80,000 years. This sounded somewhat unbelievable to me because the Gregorian repeats every 400 years. I decided to compute it for myself to double-check this figure.

I’m not Jewish and I know very little about Hanukkah, so I had to look it up. After learning that Hanukkah is based on the Hebrew calendar, the rumors were sounding more believable. The Hebrew calendar repeats every 689,472 Hebrew years. This means the correspondence between Gregorian and Hebrew calendars is about 14 billion years. That 80,000 seems lowball.

Since I decided to use Emacs Lisp for the computation, I fortunately was able to ignore all the unfamiliar, complicated rules for the Hebrew calendar: Emacs knows how to compute Hebrew dates. It can be accessed through the function calendar-hebrew-date-string.

;; Thanksgiving 2013
(calendar-hebrew-date-string '(11 28 2013))
;; => "Kislev 25, 5774"

Hanukkah begins on the 25th of Kislev, so I can write a quick-and-dirty function to detect if a date is the first day of Hanukkah.

(defun hanukkah-p (date)
  "Return non-nil if DATE is Hanukkah."
  (string-match-p "^Kislev 25" (calendar-hebrew-date-string date)))

Next I need a function to compute Thanksgiving, which is really simple. Thanksgiving falls on the fourth Thursday of November.

(defun thanksgiving (year)
  "Return the date of Thanksgiving for YEAR."
  (loop for day from 1 upto 7
        when (= 4 (calendar-day-of-week `(11 ,day ,year)))
        return `(11 ,(+ day 21) ,year)))

If there was no calendar-day-of-week I could compute it using Zeller’s algorithm, which I already happen to have implemented,

(defun cal/day-of-week (year month day)
  "Return day of week number (0-7)."
  (let* ((Y (if (< month 3) (1- year) year))
         (m (1+ (mod (+ month 9) 12)))
         (y (mod Y 100))
         (c (/ Y 100)))
    (mod (+ day (floor (- (* 26 m) 2) 10) y (/ y 4) (/ c 4) (* -2 c)) 7)))

Now for each year find Thanksgiving and test it for Hanukkah. I started with 1942 because that’s when the fourth-Thursday-of-November rule was established. Presumably due to the regexp part, this expression takes a moment to compute.

(loop for year from 1942 to 80000
      when (hanukkah-p (thanksgiving year))
      collect year)
;; => (2013 79043 79290 79537 79564 79635 79784 79811 79882)

My result exactly matches what I’m seeing elsewhere. The rumors are correct! The next coincidence occurs on November 23rd, 79043. Thanks, Emacs!

Coining Autoism

2013-08-16T00:00:00Z

I mentioned a thought to a co-worker about taking a smart phone back in time 50 years to the 1960’s, the very early days of computing. A consumer smart phone, a ubiquitous battery-powered device today, has many orders of magnitude more computing power than was available to all humankind at this time. Not to mention the amount of digital storage would be unimaginably huge. It would likely be the single most valuable device on Earth. If it goes back just a couple more decades it would significantly impact the events of World War II. What would the engineers of a half-century ago do with it?

I like to assume that it had no useful software installed, so it’s just the advanced hardware. I guess time-traveling erases digital storage in this scenario. Suppose the engineers of the day could work out a way to interface with it electronically using the technology of the time — something that I believe would be very difficult considering the bandwidth and speed of the interfaces — and use that interface to program it. Outside of study, some of the hardware would be pretty useless, such as the H.264 decoder/encoder, wireless radios (what would it talk to?), and probably the graphics chip, but the CPU would definitely be useful.

This was a time before mice, monitors, conventional operating systems, and all the modern computing paradigms. Not only was the computer hardware primitive but so were the concepts about computing. I imagine they would build and run the same sort of timesharing operating system that existed at the time. They would probably attach thousands of typewriter-based consoles to this one smart phone so that several buildings worth of people could make use of this one smart phone. Picturing in my head all these old-timey typewriters attached to a cell phone is amusing.

My co-worker said that there needs to be a word for this. Specifically, if you use time-travel to benefit yourself in some other time period. For example, something like the word “nepotism”: favoring relatives because of their relationship rather than their ability. I came up with the word autoism for this.

Crony - ism: The word “crony” means “friend.” Favoring friends regardless of their ability.
Nepot - ism: The Latin “nephos” means “nephew,” which was also a euphemism for “natural son.” Favoring family regardless of their ability.
Auto - ism: “Auto” comes from ancient Greek for “self.” Favoring yourself regardless of your own ability.

Fortunately or unfortunately, the technology needed in order to actually practice autoism, time travel, doesn’t currently exist, so the word will only be useful in science fiction for the time being.

Clay Klein Bottle

2009-04-28T00:00:00Z

A few years ago I made my wife — girlfriend at the time — a Klein bottle (well, the three-dimensional projection of one) out of clay. Since I hadn't used clay before I used some assistance from my dad. Here's how it was done,

As you can see, it's not quite the same as the generally depicted Klein bottle. The form you see here was easier to make with clay. After it was done, we baked it in a kiln. It's a bad idea to put sealed items in a kiln because they will burst as they heat. It took some time to convince the staff that our Klein bottle was actually unsealed.

Here are some pictures,

Apartment Balcony Gardening

2009-04-08T00:00:00Z

My wife was interested in growing a garden this summer. She has never done it before and wanted to learn. However, we live in an apartment so we don't exactly have a yard. Instead, we got some pots and started growing a balcony garden.

I thought we were being clever, but it turns out this is a common practice called container gardening. Searches online for "balcony gardening", "apartment gardening", and "container gardening" will bring up lots of useful information.

I think it's more convenient than regular gardening, as the plants are practically in the apartment. In fact, it's about 4 feet from our bed, through the balcony door. We can move the plants around to the other balcony, or even inside, if needed.

Gardening is a lot of fun, really.

This year, we are growing (or trying to grow) carrots, peppers, strawberries, catnip, and dactylis (cat grass). We'll see how things turn out in a couple months. Here's how it looks right now,

Two-Man Double Blind Coke vs. Pepsi Taste Test

2008-07-25T00:00:00Z

My fiancee, Kelsey, claimed that she could tell the difference between Coke and Pepsi. I wanted to put this to the test. Since there were only two of us, arranging the test wasn't a simple matter of asking someone else to pour some cups. I also wanted to do this right: testing must be double-blind. I devised a little scheme that allowed us to perform two different tests.

The first test was seeing if Kelsey or I could determine which beverage was Pepsi and which was Coke. The second was determining if there was any distinction in taste between the two drinks at all, which consisted matching two different samples together. The second test also acts as a check on the first test.

We bought one bottle of each at CVS. Next, we labeled six different cups with the numbers one though six. Each odd number is paired with the following even number. Kelsey, who was alone, used a die with an even number of sides (this includes a something as simple as a coin toss) to put one beverage in cup #1 and the other in cup #2. In this case, we used my 20-sided die I use for Dungeons and Dragons, because using it for this purpose was just full of win.

The die is important here as a random number generator. If it is left up to a human to decide what drinks go where, we may bias the setup. For example, I may be more likely to put Pepsi in an odd-numbered cup than an even-numbered one.

It is difficult for human beings to behave randomly. Try generating a list of 50 coin tosses yourself. I mean, without a coin. Just type a series of 50 H's and T's. If you examine your list of flips, you will find that you often generate very improbable series of flips (excessive heads or tails) and exhibit patterns. We need dice or coins to make decisions for us in this experiment.

To do it right, the beverage must be chosen before the roll: "I will be pouring Pepsi now.". Roll the die. If it rolls an odd number, pour the drink into the odd cup (#1). Write this information down and keep it secret.

Next, after allowing the foam to calm down (which might accidentally reveal information to me), Kelsey leaves the room and I enter. I perform a similar procedure to distribute the drinks into cups #3 and #4, then #5 and #6. I keep track of what drink, #1 or #2, goes into what cup. I keep it secret. These last two cups are for the purpose of the second experiment.

At this point Kelsey knows what was in cups #1 and #2, but not where they went. I know where they went, but not what was in the cups. Together we know everything, but individually we know nothing.

In order to make the second test double-blind, and allow me to participate, I leave the room. Kelsey rolls the die. If it rolls odd she switches the label on cups #5 and #6. It is important that these cups are identical. One flaw potential, however, is that the liquid in each cup may look unique. One may be more fizzy or one cup a little more full. Noticing this may happen subconsciously, which is the whole point of doing double-blind tests.

Ok, we didn't actually do this last part because I didn't think of it till later.

We sample all four cups (#3 - #6) in pairs, alone, making notes on what beverage we think is in what cup. Once we are both done we share our secrets and see how well we did.

Our results? Neither of us could tell the difference between Coke and Pepsi.

Up is Down

2008-06-26T00:00:00Z

I was in an elevator the other day and I noticed something about the digital numbers. I was on the 7th floor going down. Inside the elevator was the standard 7-bar number display indicating the current floor,

However, from the angle I was standing, the top right bar was not visible. Like this,

The arrow was indicating that the elevator was traveling downward, but with that bar in the way the numbers can appear to be going upwards, not downwards. It is an ambiguity, as without that bar, 6 is equivalent to 8 and 5 is equivalent to 9. One version is covered, the other is not.

At first I thought this was simply some kind of quirky behavior of the elevator. "Why is it going up when the arrow points down? Seems like bad design to me!", I thought — until we got to floor 4, where it was obvious what was going on.

"Oh... now I feel foolish."

My Team Won the Robot Competition

2008-02-04T00:00:00Z

Introduction:
This "news" is over two months old, simply because I had other more interesting things to write about first. Not that I am out of ideas: I have at least three more ideas lined up at the moment on top of several half-written entries that may never see the light of day. I just want to get it out of the way.

Robot Competition 2007

In December we held the robot competition, pitting against each other the robots that we spent the semester building. It was a double-elimination bracket with five teams. Teams competed by arranging the maze (within the rules) and deciding the initial position for their opponents. The robots do not get to know about the maze or where they are starting; they must figure this out on their own by exploring the maze.

To recap, there was an 8'x8' game area containing a 4'x8' maze of 1-square-foot cells. On the floor of the game area was a grid of white lines on black, where the white lines were about 7-inches apart. The robot started at an unknown position and orientation in the maze, which was also set up with a configuration unknown to the robot. In the non-maze open area, three small wooden blocks were placed at the intersection of white lines, with a steel washer attached to the top of each block.

In short, the robot had to move all three blocks to the repository, a pre-programmed position in the maze.

At the end of the semester, our team's robot was the only one that could successfully complete this task. The other teams needed to play in a degraded mode: known maze configuration, known starting position, known block positions. The loser bracket played this degraded version of the game. Because of this, our team was able to sweep the tournament with a perfect run. All the robot had to do was successfully run the full game. The competition, not being able to do this, automatically lost.

The robots were mostly the same, except for one team who had a robot with 4 multi-direction wheels. Every other team made a "scooter bot" type of robot: two powered wheels (with casters for balance) and chassis with three levels. The first real separation of design was when it came to picking up blocks. Each team initially had a different idea. One team was going to build a pulley system to lift the blocks. Another was going to use sweeping arms to sweep in the block. Another was going to used a stationary magnet.

Our team went with a rotating wheel in front with magnets along the outside (see images below). Once a block was found, the robot would rotate a magnet over the block, then rotate the attached block out of the way. In the end, four of the five teams ended up using this design for their own robots (the last team stuck with the stationary magnet).

These pictures were taken about a month before the competition. The wiring job was still a bit sloppy and the front magnet wheel lacks tiny magnets attached to the outside. Other than that, this is what our final robot looked like. In that last month, we attached the magnets, cleaned up the wiring, and made a whole bunch of code improvements making the robot more robust.

I will now attempt to describe some of the things you see in these images.

On the bottom of the robot you can see two casters for balancing the robot (big clunky things). You can see an IR sensor, which is pointing at the blue surface attached to the other side of the robot. This was the block detection sensor, a home-made break-beam sensor. And finally, you can see three LED lights on top of a long circuit board. This is a line tracker, with three sensors that can see the white grid on the bottom of the game board. The line tracker is how the robot navigated the open area of the board. It went back-and-forth looking for blocks, using the line tracker to stay on the line.

Also attached to this bottom layer are the powered wheels, with blue rubbers for traction, and their wheel encoders. There are spokes on the inside of the wheels (encoder disks), and the wheel encoders send a signal to the micro-controller each time it sees a spoke. The software counts the number of spokes that passed, allowing the robot to keep track of how far that wheel has turned. This information is combined with IR distance sensors to give it a very accurate idea of its position.

On top of the bottom black layer, you can see four distance IR sensors for tracking walls in the maze. They checked to make sure the robot was going straight (that's why there are two on each side), as well as map out the maze as it travels long. Hanging down from the bottom of the red layer is another IR sensor facing forward, looking at walls in front of the robot. Mounted on the front is the block retrieval device (lacking magnets at this point).

On top of the red layer are two (empty) battery packs, which holds 9 AA rechargeable NiMH batteries. This actually makes two separate power systems: a 4-pack for motors and a 5-pack for logic (micro-controller et al). In the circuit, the motors, containing coils of wire, behave like inductors, which could cause harmful voltage spikes to the logic. Separate power systems help prevent damage.

On top is the micro-controller and all of the important connections. The vertical board contains the voltage regulator and "power strip" where all of the sensors are attached. It also contains the start button, which was connected to an interrupt in the micro-controller. The micro-controller had its own restart button, but once the system started up, initialized, and self-calibrated, it waited for a signal from the start button to get things going.

I was about to post this when I was reminded by my fiancee that she took pictures at the end-of-semester presentation, after the competition. Included are some images of the robot after it was completely finished. Yes, that is a little face fastened to the front.

If you are ever at Penn State and are visiting the IST building, you can see the robot. Because the robot won the competition, it is on display and will be for years to come. You can recognize it by its face.

I have made the final robot code available here: final-robot-code.zip. I was the software guy, handling pretty much all the code, so everything here, except interupt_document.c was written by me. It's probably not very useful as code, except for reading and learning how our robot worked. There are a few neat hacks in there, though, which I may discuss as posts here. It's not noted in the code itself, nor in the zip file, but I'll make this available under my favorite 2-clause BSD license.

Movie Montage Poster

2007-12-30T00:00:00Z

I wanted to try making one of those movie montage things I wrote about earlier into a nice poster that could be hung on a wall. Now, I prefer a Spartan environment whenever possible, so I really did not want to have my own poster. No decorations for me, please. I just wanted to make one. My solution? Make one for my sister, who has lots of junk and would enjoy having one. Her favorite movie is Pirates of the Caribbean, so I used this movie, which she conveniently already had on DVD.

As before, I used mplayer to rip all of the frames I needed. To get a poster-quality version I would need better resolution. To do this, I changed the frame output image size to 160x90 (100 times bigger than before).

framestep=30,scale=160:90

Next, I used my own montage script to put these frames together. My script took about 2 minutes to put together one of these larger montages. Finally, I used the Gimp to add a black border and simple title at the top. Since I don’t have any more than 512MB of memory on my computers, I actually had to scale the image down to 1/4 of its original size to do this. Before scaling, the GIMP was spending hours just adding the border because it was thrashing the hard drive. It needed about 2G of memory and it was using the hard drive to get it.

I took my giant image to FedEx Kinko’s where they printed it to a 2’x2’ poster for 30 bucks. Here are the results, taken using my sister’s crappy Kodak camera (never buy Kodak digital cameras, as they all suck!). To help see what is going on, I provided a glare version and a non-glare version. Each shows different details.

Here is the normal version from before for comparison.

Robot Version 1

2007-10-16T00:00:00Z

Update: There is a followup post to this post.

Full Album

Here is what my team has been working on for the last couple weeks. The end goal for this robot is to escape a maze, collect blocks, and find a repository in which to drop those blocks. Someone suggested we call it Pac-man.

We added a third level to make more room for the batteries and extra sensors. The game board is 8x8 feet with a 4x8 foot maze.

Building a robot is an interesting experience, but a stressful one. Especially when you are doing it for a class. So many things could go wrong and you can spend hours tracking down a bad soldering job, which we once found inside an IR sensor. It was a poor manufacturing soldering job.

So, as of this writing, the robot uses 3 infrared (IR) sensors to look at walls and two wheel encoders for tracking the distance traveled by each wheel. You can see the disk encoder on the inside of the wheel in the second robot image. The robot uses 9 rechargeable nickel-metal hydride (NiMH) AA batteries: 5 for the Freescale 68HC12 micro-controller and sensors, and 4 for the continuous rotation servo motors. It is a competition, so I don’t want to give too many details at the moment in case another team is reading.

Right now it limps along in the maze and gets around for awhile before drifting into a wall. This will get fixed this weekend, as our grade depends on it. We just need to make better use of our sensors. I.e., it is a software issue now.

Eventually, I will put some code up here we used in the robot. It is all done in C, of course.