Conway's Game of Life

Four rules, no player, and more behaviour than they have any right to produce.

Generation 0 Alive 0

Drag across the grid to draw cells, or drag over live ones to erase. A live cell with two or three live neighbours survives; with fewer it dies of isolation, with more of overcrowding. A dead cell with exactly three live neighbours comes alive. The grid wraps at the edges, so a glider that leaves the right-hand side comes back in on the left.