Leopard pattern generator

Grow a big cat's coat the way a two-stage Turing model says the leopard grows its own: two chemicals react and diffuse until they settle into spots — the flecks of a cub — and as the animal grows, a few parameters shift and the spots open into rings and break into rosettes. Or make an instant procedural coat. Every pattern tiles seamlessly, can be fur-shaded, exported, and tried on a 3D cat.