Game of Life Pattern Generator
Four rules, applied to a grid, and a question that cannot be answered by looking: what does this pattern end up doing? A random soup either dies out entirely, freezes into a still life, or falls into a repeating cycle. This runs each soup until one of those three happens, and detects the third by remembering every state it has seen — so the period reported is the exact one, not an estimate.
What this generator does
Fills a grid at the density you choose and applies Life's rules generation by generation, stopping as soon as everything is dead or a state repeats. You can step through every generation it kept, forwards or backwards.
How to use this tool
- Choose the grid size and how much of it starts alive.
- Run it, and read what it settled into.
- Step back and forth through the generations to see how it got there.
- Seed a soup that did something interesting so you can show it to someone.
Understanding the controls
- Grid size
- Between 6 and 24 cells across. Small grids settle quickly; larger ones take longer and more often keep changing.
- Starting density (%)
- How much of the grid starts alive. Very low densities die out at once and very high ones die of overcrowding; around 35% is the liveliest.
- Generations to try
- The ceiling, not the count — it stops as soon as the pattern settles, and says so if it never does.
- Seed
- Reproduces the same starting soup, which is the only way to show someone else a particular pattern.
- Previous / next generation
- Steps through the history that was kept, so you can watch how the ending was reached.
Common use cases
- Finding oscillators and still lives without hunting for them by hand
- Showing that the same rules give three completely different endings
- Teaching the four rules on a pattern that is genuinely unpredictable
- Comparing what different starting densities tend to produce
- Reproducing an interesting soup exactly from a seed
How this generator works
A live cell survives with two or three live neighbours and a dead cell comes alive with exactly three. The border is dead rather than wrapped, so anything leaving the grid is lost — that is what makes settling detectable. Every state is hashed as it is produced, and a repeat gives the exact period. The check re-steps every generation and compares.
Randomness and fairness
Only the starting soup is random; every generation after it follows deterministically from the four rules. Seeded soups reproduce exactly and are therefore explicitly not cryptographically secure. Without a seed the browser's cryptographically secure generator fills the grid.
For how randomness is produced across the whole site, see how Generate Random works.
Limitations and good to know
- The border is dead rather than wrapped, so gliders reaching the edge are destroyed rather than reappearing.
- Grids stop at 24 cells across, which is far too small for the large engineered patterns Life is famous for.
- A run that has not settled within the generations allowed says so — it does not mean the pattern never settles.
- There is no editor: you cannot draw a starting pattern, only seed a random one.
- Runs are not stored between visits.
Privacy and your data
The grid and every generation are computed in your browser. Nothing is transmitted, and nothing survives the visit.
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