Functional Geometry

I usually use the 'image' library to experiment with 2D algorithms. It's fast loading and renders to gif, without having to worry about the mechanics of interactive screen update, etc.

I know it's bad-form to document other people's code, but I took the liberty to generate an ediman from the well documented sources and wrote an example:

http://mahmud.arablug.org/image-docs/

Racket's 2htdp/image module is arguably more fully-featured implementation of the same thing (though it should be fairly simple to add colors to Frank's code)