I thought this was worth posting. Sean Plott and I combined our library research to create this sandy, colorful little number. I like it. It's very mesmerizing. When you're done with your drawing, try clicking to "shake the etch-a-sketch". Note that the color is changing to the beat of the music.
Requires traer physics library and minim library:
http://www.cs.princeton.edu/~traer/physics/
http://code.compartmental.net/tools/minim/
"Also, you'll need to put an mp3 file in the same directory as the processing project and replace "missyou.mp3" with the appropriate song filename. I can't upload missyou.mp3 due to copyright purposes."
Thank you.
-jim