Conway's Life

One rule on a grid of cells, and a universe that can compute anything.

Step 1 / 7

One rule

Every cell looks at its eight neighbours. An empty cell with exactly three comes alive. A live cell with two or three stays. Every other cell dies or stays empty. The ghosts show what happens next: white are births, amber are deaths. Press Step.

B3/S23

3 An empty cell with exactly three neighbours is born.
2–3 A live cell with two or three survives.
else Any other live cell dies, of loneliness or crowding.

Pause and hover a cell to see which line applies.

Still lifes

Every cell has two or three neighbours and no dead cell has three. Nothing changes.

Oscillators

They return to the same shape after a fixed number of generations, the period.

Spaceships

They return to the same shape somewhere else, so they travel.

Methuselahs

A handful of cells that take thousands of generations to settle.

Infinite growth

Patterns whose population grows forever.

How patterns in Life send each other messages, one glider at a time. Every step is a real pattern running on the board.

1
A glider is a bit
Five cells that keep their shape while they travel. Where a glider is, read a 1. Where one is missing, read a 0.
2
A gun is a clock
The Gosper gun fires a glider every 30 generations: a wire carrying 1, 1, 1… forever. Every signal below runs on this beat.
3
An eater is a receiver
Seven cells that swallow a glider and repair themselves within four generations. Point a stream at one and it eats forever.
4
Two guns talk
A second gun fires across the first. At this offset every pair of gliders meets at the crossing and both vanish without a trace.
5
A collision is logic
Feed the crossing a stream with gaps. A clock glider only gets through where the data has a gap, so the output is the data inverted: a NOT gate.
NOT gate, bit by bit
Data
Out
6
Send a message
Type up to 4 characters. Each one becomes 8 bits. The sender's tape keeps an eraser for every 0, so only the 1s reach the receiver, where the lamps read them.
Message

Where this goes

The board is 1024 × 1024 cells. Anything that reaches its edge is erased, so streams leave cleanly instead of wrapping round.

NOT gate, bit by bit
Data
Out