Some amazing generative art, done with Processing, here: <a href="http://complexification.net/gallery/" rel="nofollow">http://complexification.net/gallery/</a><p>You can grab the source for these and play around with them, tweaking values to see how things work.<p>One of my favorites is Sand Traveler. The underlying algorithm is relatively simple, but the results are stunning.<p>These are presented as Java applets, but Processing 2.0 now lets you export code to JavaScript (processing.js).<p>It also exports to Android apk files, so you can build Android apps with Processing.