picksickles: some optimizations:

 * only calc velocity once

 * flat array of particles, dumbass

 * don't even create invalid particles

 * precompute stroke style

 * better example image
picksickles: MORE PHYSICS!

Track acceleration, bounce particles off of walls, loop forever.
picksickles: physics tweaks for better effect

 * don't convert angle to radians
 * velocity starts at zero
 * smaller initial acceleration
picksickles: title + description