The classic cellular automaton, as an open sandbox. Toggle any cells you like, then press Play and watch the simple birth/survival/death rules produce surprisingly complex patterns.
Rules
Click any cell to toggle it alive or dead before you start.
Press Play to watch generations advance automatically, or Step to advance exactly one generation at a time.
A live cell survives with 2 or 3 live neighbours; a dead cell becomes alive with exactly 3.
There's no win or lose here — Clear resets the grid, or just keep experimenting with patterns.
Tips
Try a row of 3 cells (a "blinker", which oscillates in place) or a small 5-cell diagonal shape (a "glider", which crawls across the grid forever) — both are classic starting patterns worth knowing.