I asked my math teacher if she knew what these were and how they worked. She didn't know, so I figured it out. This was actually really easy and fun to make.
It's really easy to exit Emacs, because it doesn't have the horrible distinction between insertion mode and command mode. That's why people have trouble exiting vim. Just sayin'. (Yeah I get that it was a joke.)
Sigh, I'm supposed to yell at you about pointers to external web sites. I'm getting tired of trying to enforce that. (I have been reading a book, The Picnic, which is about the fall of the Iron Curtain, and there's a lot in it about the state of mind of East German and Hungarian functionaries whose job was to stop people doing what they overwhelmingly wanted to do.) I keep trying to discuss the ToS with our team but there are always more fun things to talk about, such as Jens's latest experiments in dev. Sorry for hijacking the thread, now back to your discussion of Bézier curves.
P.S. Speaking of which, really nice explanatory project!