Drag cursor left or right to interact.
Particles rotating around the center of the screen in isometric space.
This is my second Processing program, but first to the site. I did my best to comment the whole code.
Updates:
November 6, 2009 - optimization
December 2, 2009 - more optimization, some revising in code and comments, using PVector instead of floats for coordinates now, and inverted the speeds (center moves faster than outer)
December 3, 2009 - Added interactivity. Drag cursor left or right (while pressing) to spin, also revised codes a bit.