Two virtual chemicals, A and B, are diffused across a lattice each step. A is fed in at rate f; B is removed at rate k; where they meet, A + 2B → 3B. Nothing else. From this the sheet grows fingerprints, leopards and brain coral.
Drag across the slide to inoculate it with B. Drag on the parameter map to slide continuously between regimes — the border between spots and stripes is where the strangest tissue lives. Photograph saves the current frame as a PNG at native slide resolution.
Pearson's 1993 taxonomy of Gray–Scott states gave these regimes their Greek letters. Here they are given lab names instead: Coral, Mitosis, Worms, Spots and Maze. The brass tag updates with whatever culture is currently on the stage.