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/