Rule · Life-like automaton
HighLife (B36/S23)
Change one digit in Conway's Game of Life and you get a rule capable of something Conway's original can't do: HighLife supports a small pattern that copies itself, indefinitely, entirely as a side effect of one extra birth condition.
One Digit, One New Capability
Conway's Game of Life is B3/S23: a dead cell is born with exactly 3 living neighbors. HighLife adds a single extra birth condition — a dead cell is also born with 6 living neighbors — written B36/S23. Survival stays identical to Conway's rule. That one addition sounds minor, but it opens up a capability Conway's Life provably doesn't have on its own: a compact HighLife pattern exists that, after a fixed number of generations, produces two separated copies of its own starting shape, each of which goes on to replicate again the same way.
Why It Matters
HighLife is one of the clearest illustrations of how sensitive Life-like automata are to their exact birth/survival digits — a single extra neighbor count in the birth rule is the difference between "no self-replication is known to exist" and "a self-replicating pattern exists and has been found." It's a useful rule to explore right after Conway's Life specifically because it shares the same survival behavior, so familiar shapes like still lifes and gliders carry over, making the contrast from the one changed digit easy to isolate.
See It Live
Open HighLife pre-loaded in Cellscape and randomize the grid — compare it side by side with Conway's Life on an identical starting pattern to see exactly where the extra birth condition changes the outcome.
Frequently Asked Questions
What's the difference between HighLife and Conway's Game of Life?
Conway's Life is B3/S23. HighLife is B36/S23 — identical except a dead cell with exactly 6 living neighbors is also born, in addition to the usual 3. That single extra birth condition is enough to give HighLife a self-replicating pattern that Conway's Life doesn't have.
What does "self-replicating" mean here?
A specific small HighLife pattern, when run forward, produces two separated copies of its own original shape after a fixed number of generations — and each of those copies goes on to replicate again, the same way Life's glider gun produces gliders, but replicating the entire generating structure rather than a smaller traveling pattern.
Does HighLife still have gliders and other Life-like patterns?
Yes — because the survival rule (S23) is identical to Conway's Life, many still lifes, oscillators, and spaceships that work in Conway's Life also work unchanged in HighLife. The extra B6 birth condition adds new behavior on top rather than replacing the old rule entirely.
See how HighLife fits among other Life-like rules in the complete guide, or browse the full pattern & rule gallery.