If you're curious, the "readable" version is here: http://bytex64.net/code/datasnake/snake.html

I started out writing it as straightforward as possible, then applied functional tricks to slim it down. That was a lot of fun. I'm not sure how to post a code snippet here, but I'll try to illustrate one of my favorite portions.

In the original, I did key input with a switch statement. That got replaced by:

    { 37: P(-1,0), 38: P(0,-1), 39: P(1,0), 40: P(0,1) }[e.keyCode]

"But wait!" you're thinking, "What happens when e.keyCode is less than 37 or more than 40?" What happens is it evaluates to undefined, and it errors out in the M() function, effectively short-circuiting it. If you look in your browser's error log, it'll spew an error every time you hit another key. It's lazy, but it works. :]