In the Arduino Club (see website for details), we are making a snake game to be played on an LED matrix.
I wrote this very simple code so we would all be on the same page when translating the same logic to C syntax.
In addition, I also threw the same logic into my 3d JS Engine (zengine.js) because why not?
Oh and the file 2dCircular.html will play identically to 2d.html but internally uses a circular buffer to store the snake as this is cleaner to implement in C (for the real thing).