Pulsating

Classic rule · B4-6/S3-4

Blobs expand and collapse in cycles.

How the rule works

It has no start of its own: it opens on the world you have, and Random shape tries others.

Notation

Birth/survivalB4-6/S3-4
Softology, MCell (S/B/C/N)3-4/4-6/2/M
Weighted countingB12,15,18/S9,12 (faces count 3, edges 2, corners 1)
NeighbourhoodMoore (26 cells)

B lists the neighbour counts at which an empty cell is born, S those at which a live cell survives, and C the number of states. How to read a rule

More classic rules

All 30 rules · From 2D to 3D: why Conway's rule needs changing in 3D