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DryLife rule
Rulestring 23/37
Rule integer 6280
Character Explosive
Black/white reversal B0123478/S0234678

DryLife is a Life-like cellular automaton in which cells survive from one generation to the next if they have 2 or 3 neighbours, and are born if they have 3 or 7 neighbours.


The "flower garden".

DryLife is so named because the standard spaceships from normal life; lightweight spaceship, middleweight spaceship, and heavyweight spaceship — also known as "fishes" — do not work, though the glider does. Some other spaceships, such as the weekender and loafer, work in this rule. The copperhead evolves into the closely related c/10 goldenhead, differing from copperhead by two cells in one phase.

Two correctly spaced B-heptominoes (as in the twin bees shuttle) act as a c/2 orthogonal puffer.

A new speed allowed by DryLife is 9c/28 orthogonal. Technology travelling at this speed relies on the R-pentomino. There is a small 9c/28 orthogonal pond puffer, and a 9c/28 spaceship. Guns and breeders have been constructed that fire spaceships and rakes of this speed respectively.

The "flower garden", a common constellation which evolves from honey farm predecessors, composed of two bi-boats and two cis-mirrored R-bees, is shown to the right.


There is a proof sketch of this rule's universality. It is on conwaylife forums[1], which contains a proof-scheme covering all rules that support glider and their rulestring matches B3[678]*/S23[678]*.


  1. "List of the Turing-complete totalistic life-like CA".

External links

  • DryLife at David Eppstein's Glider Database