nullprogram.com/blog/2009/04/28/
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,