Patterns to drop in
Pick one, then click the grid where you want it. These are the objects people usually come looking for:
The rule string
Conway’s Life is only one member of a family. The notation B3/S23 reads: a dead cell is born when it has exactly 3 live neighbours, and a live cell survives on 2 or 3. Every other count kills it. Type any combination of digits 0–8 into the rule box and the grid switches immediately — the current cells are kept, so you can change the physics mid-run and watch a stable pattern come apart.
| Rule | What it does |
|---|---|
B3/S23 | Conway’s Life. Sparse, long-lived, supports gliders and universal computation. |
B36/S23 | HighLife. Same as Conway plus birth on 6, which is enough to produce a self-replicating object. |
B2/S | Seeds. Nothing ever survives a generation; the whole pattern is pure explosion. |
B3678/S34678 | Day & Night. Symmetric under swapping live and dead, so it grows blobs with structured coastlines. |
B1357/S1357 | Replicator. Every pattern copies itself, fractally, forever. |
B3/S012345678 | Life without Death. Cells never die, so it fills space like a crystal or a maze. |
What the density trace shows
Fill the grid at random and the population crashes almost immediately, then keeps sagging for a very long time. That second phase is the interesting one. Running Conway’s rule on a 384×384 torus from 18 different starting densities gives a result that surprises most people: starting anywhere between 12% and 70% — a six-fold range — lands in the same place, a density of 0.033 to 0.038 after 2,000 generations.
What the starting density changes is not the destination but the time taken to get there. Starting at 37.5% takes the longest to calm down — about 307 generations before the density first drops below twice its final value — while very sparse and very dense soups are decided within a generation or two. Try it: fill at 5%, then at 38%, then at 90%, and watch the trace.
“Settled” is also an approximation. Left running to 10,000 generations the density is still falling — 0.0927 at 100, 0.0431 at 1,000, 0.0366 at 2,000, 0.0291 at 10,000 — roughly a fixed decrease per tenfold increase in generation. The ash is never quite finished: a stray glider eventually crashes into a still life and knocks a bit more out of it.
The grid wraps
By default the edges are joined, so the grid is a torus and a glider that leaves the right side comes back on the left. Untick Wrap edges to treat everything outside as permanently dead, which is what you want for infinite-growth patterns you would rather not have collide with themselves.