Two chemicals, two equations, infinite patterns. The Gray-Scott model produces spots, stripes, coral, and waves from local diffusion and reaction alone.
The Gray-Scott model describes two chemicals U and V reacting on a surface. U is continuously fed into the system and replenished at rate f. V is produced when U and V meet (the autocatalytic reaction U + 2V - 3V) and removed at rate f + k. The interplay between diffusion and reaction produces the patterns.
The feed rate f and kill rate k are the two parameters that determine which pattern regime emerges. Small changes produce completely different structures -- spots, stripes, spirals, or chaos. Alan Turing predicted this class of behavior in his 1952 paper "The Chemical Basis of Morphogenesis," proposing it as the mechanism behind animal coat patterns and embryonic development.
Click or drag on the canvas to introduce new seeds of chemical V. Use the presets to jump between pattern regimes, or tune f and k manually to explore the parameter space.