whatA row of cells, on or off. Every beat each cell looks at itself and its two neighbours, three bits, eight possible sights, and consults an eight-entry lookup table for what to become. That table is the entire physics of a universe, and there are exactly 256 of them. The table stands at the top with a verdict under each sight: click a verdict to flip that bit of physics while the world runs; click the field to cycle the four famous rules.

whyThe claim: three neighbours and a lookup table span the whole bestiary. Rule 30 pours randomness from one seed cell -- its centre column measured here at a full one point zero bits, a perfect coin. Rule 90 draws the Sierpinski triangle: the count of live cells in row n is exactly two to the number of ones in n's binary name, verified along the ladder to row 63. Rule 110 hosts gliders enough for proven universal computation. Rule 184 is traffic: cars conserved to the last one, jams dissolving below half density and persisting above it.

howOne generation per beat on a ring the width of your screen, drawn like a spectrogram scrolling upward. The print replays the current rule from its canonical start at coarse scale. One integer seeds the random roads, so the same seed jams in the same places.