After looking around a little, while there are a ton of very impressive projects to look at, I am sure they were huge undertakings. The one I found that seems like I would enjoy using as a guideline for a project reminds me of a toy I love as a kid... Spiral-Doodle or something like that. You draw around and it makes a symmetrical sketch of surprising intricacy. This is works on that premise but without the locked in discs creating pre-designed results using your mouse and I find it fun to play with still. Here is the link to the app they have posted.

http://oimotabe.com/processing/20/

Don't see any code for it, but that's likely ok. It's not the most complicated seeming program, but I am a fan of the results even if more often than not it looks like a bunch of scribbles being drawn.