Two chemical species U and V react: U+2V→3V (autocatalysis) and V→P (inert). Tuning feed rate F and kill rate k produces spots, stripes, labyrinthine and self-replicating patterns.
Click canvas to add V
Gray-Scott (1985) parameterized by (F, k). Pearson (1993) mapped the full phase diagram revealing 12 distinct pattern classes. The autocatalytic term U·V² creates Turing-like instabilities; spot replication (mesa instability) occurs when F≈0.037, k≈0.060.