A simple 1D cellular automaton that generates provably random output — used in Mathematica's RNG
Rule 30 is a 1D elementary cellular automaton discovered by Stephen Wolfram. Each cell is 0 or 1; each generation, a cell's new value depends on itself and its two neighbors (8 possible patterns → 1 byte = the rule number). Rule 30 appears random yet is fully deterministic — its center column passes many randomness tests. The cone snail Conus textile has a shell pattern that resembles Rule 30.