GRAY-SCOTT
Reaction-diffusion. Two chemicals feeding and killing each other on a GPU.
Click to seed. Drag to draw. Patterns emerge from the math.
dU/dt = Du*laplacian(U) - UV^2 + F(1-U) | dV/dt = Dv*laplacian(V) + UV^2 - (F+k)V
GPU via WebGL fragment shaders. Howard Braham suggested this.