Nice work. I talked about the effect back at http://paulirish.com/2010/my-harmonious-background-canvas/

And the equivalent code is available on Github: https://github.com/paulirish/harmony

Thanks for the code, it's awesome fun to play with. :)

To those wondering:

Harmony procedural drawing tool, by mrdoob: http://mrdoob.com/projects/harmony/

dollar recognizer project (draw a star on paul's background!): http://depts.washington.edu/aimgroup/proj/dollar/

inspired by paul's site's implementation, about a year ago, i made a proof of concept captcha thing ("motioncaptcha"): http://www.josscrowcroft.com/demos/motioncaptcha/