The rules of the game are simple. What’s amazing is the complex effects they create.
The game starts by setting up the game board, or grid, with a pattern. One colour represents cells that are ‘alive’. Another colour shows those that are ‘dead’. The game starts and play moves to the next round, or generation.
To decide which cells are alive in the next generation, only two rules are used:
…it lives in the next generation if it has 2 or 3 living neighbours.
In other words: If a living cell has 0 or 1 living neighbours, it will die (of loneliness). If it has 4 or more living neighbours, it will die (of overcrowding) .
… it comes to life in the next generation if has exactly 3 living neighbours.
The rules are applied to every cell in the grid simultaneously.
We must look at each cell’s neighbours to decide if that cell is alive in the next generation. We record that on the next grid, then look at the next cell in the current generation, then repeat till all are done.
A cell’s neighbours are the 8 cells that surround it. In the graphic below the central cell is alive (shown black) and its neighbours are highlighted.