Aggregation, the board game

• A coin and a chess board
• Place a counter on one of the bottom left square of the board

Repeatedly

• Place a counter on one of the top right square of the board

For each counter

• Toss the coin
• If it's a head move the counter down a square
• If it's a tail move the counter left a square
• If the counter is adjacent to another counter stop
• If the counter moved off the board stop

The game ends when the counters form a line from bottom left to top right.

This game implements Diffusion-limited aggregation.