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."