July 23, 2026
A new spaceship, found in a universe one rule away from Life
A 19-cell pattern that swims: the second known ship of its kind in the cellular automaton B3/S236, discovered by exhaustive computer search — along with a proof that, below a certain width, it and its one known sibling are the only two that exist.
The universe it lives in
Conway's Game of Life plays out on an infinite grid of cells, each alive or dead. Every tick, each cell counts its eight neighbours: a dead cell with exactly 3 live neighbours is born; a live cell with 2 or 3 survives; everything else dies. That rule is written B3/S23.
Change the recipe slightly and you get a different universe. B3/S236 adds one condition: a live cell with six neighbours also survives. Almost everything about Life carries over — the famous glider still glides — but Life's classic mid-size spaceships (LWSS, MWSS, HWSS) are all killed by that extra survival, so this universe has to grow its own. Until now its public census listed exactly one spaceship: the glider.
What you're looking at
A spaceship is a pattern that reproduces itself, shifted, after a fixed number of ticks. The ship above repeats every 2 generations, moving 1 cell each time it does — half the speed of light of this universe, written c/2. It breathes as it swims: 19 cells in one phase, 20 in the other.
The two ships are genuinely different objects — not rotations, reflections, or phases of one another. Both oscillate between 19 and 20 cells, so the new ship ties the smallest known population for a ship of this speed here rather than beating it. (An early report claimed it was one cell smaller; that compared one ship's small phase against the other's large phase, and is corrected here.)
It only lives in this universe
Run the very same 19 cells under Life's ordinary rule and the pattern tears itself apart in a few generations — the ship depends on that one extra survival condition. Watch it fail:
Why we believe it's new
| Check | Result |
|---|---|
| Re-simulated by an independently written engine (no shared code) | period 2, displacement 1, confirmed |
| Re-verified a third time by another program written from the rule definition alone | confirmed |
| Canonical ID (apgcode) computed locally, validated against 37 known objects, then accepted by Catagolue's own server | xq2_c4ti1isz0311 |
| Catagolue census of B3/S236 | no sample soups — unrecorded |
| Eppstein's glider.db (the historical ship database) | absent — its only B3/S236 period-2 entry is the sibling ship |
"New" here means: absent from the two places the community records such ships, after a deliberate search. The final word belongs to the community itself — submission to the ConwayLife forums and Catagolue is the step that makes it official.
And a small completeness theorem
The search that found the ship was not random — it was an exhaustive enumeration, in the style of Eppstein's gfind: build the ship column by column, tracking only what the rule needs to extend it, over every possibility within a strip seven cells wide. The search completed — 1,799,962 states, nothing pruned, nothing skipped. The result is stronger than a discovery:
Within a strip of width 7, at speed c/2 and period 2, these two ships are the only spaceships this universe contains (up to length 60, and up to a formally-stated one-in-ten-million hashing caveat detailed in the paper).
The same machinery, pointed at Life as a sanity check, rediscovers the LWSS from nothing in seconds and correctly reports that nothing thinner exists — the searcher earns its exhaustiveness claims.
The patterns
Copy either block into Golly or any Life-like simulator:
x = 7, y = 7, rule = B3/S236 2bobo$3bobo$3o3bo$obo3bo$2b2ob2o$b3o$bo!
x = 8, y = 7, rule = B3/S236 bo$bob2o$4b3o$6b2o$ob2ob2o$o2b3o$3b2o!
Or download them: the new ship · the sibling.
The paper
The full write-up — the search method, the exact scope of the exhaustiveness theorem, the verification chain, and its caveats — is a four-page note:
Fine print
Found July 23, 2026, by an exhaustive de-Bruijn row search designed and run by Claude Fable 5 (Anthropic), directed by Scry Visuals, as part of a broader autonomous-search campaign. Verified by three independently written simulators; canonical codes validated server-side by Catagolue; census absence checked the same day. A short paper with the method, the exact scope of the exhaustiveness claim, and its caveats accompanies this page. The searched frontier (all rules, speeds, and widths attempted, finished or not) is logged so the search can continue where it left off.