billiards

Particles bouncing around inside a fractal. The walls are built from a generated tile - a carpet, a net, an H-tree - so instead of a flat table you get a chamber full of holes and narrow corridors, and the particles smear a slowly fading trail behind them as they travel. The simulation is seeded and runs the same whether it is drawn on the CPU or handed to a GPU shader.

Playing

• Tap any open cell to break a fan of particles outward from that spot. Taps on a wall are refused.
• Each break adds to what is already bouncing, so the table fills up as you play.
• design, number and level choose the fractal; padding and subpixel set its border and detail.
• speed, size and count set how the particles move and how many arrive per break.
• trail controls how quickly the painted trail fades. play pauses everything.