Conway's Game of Life

Rules (source: Wikipedia):

1. Any live cell with fewer than two live neighbours dies, as if caused by under-population.
2. Any live cell with two or three live neighbours lives on to the next generation.
3. Any live cell with more than three live neighbours dies, as if by overcrowding.
4. Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.

The grid is a torus, so the edges wrap around. Mouse over a cell to see its neighbors.

If the animation is paused, you can click/drag across individual cells to change their states.