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x=0, y = 0, rule = B37/S23 ! #C [[ THEME Inverse ]] #C [[ RANDOMIZE2 THUMBLAUNCH OFF THUMBNAIL THUMBSIZE 2 GRID ZOOM 4 WIDTH 500 HEIGHT 500 LABEL 90 -20 2 "#G" AUTOSTART PAUSE 2 GPS 8 LOOP 256 ]]
LifeViewer-generated soup (refreshes with page)
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 rule behaves in an explosive manner, as small patterns, such as the stairstep hexomino, may exhibit chaotic growth.


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 x66, 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, and it supports the pseudo-tagalong in fireship as well.

A pair of correctly spaced B-heptominoes (as in the twin bees shuttle) evolves into a messy period-160 c/2 orthogonal puffer.

x = 19, y = 15, rule = B37/S23 4b2o$b2obo9bo$o$o12bo$3o8bob3o$12bo3bo5$4b3o6bo$4bo11bo$4bo$5b2obo6bob 2o$8b2o5bobo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ ZOOM 16 HEIGHT 350 AUTOSTART GPS 7 TRACKLOOP 28 -9/28 0 ]]
A 2-engine 9c/28 spaceship found by Paul Tooke
(click above to open LifeViewer)
RLE: here Plaintext: here

A new speed allowed by DryLife is 9c/28 orthogonal. Technology travelling at this speed relies on the R-pentomino. Two R-pentominoes constitute a small symmetric 9c/28 orthogonal pond puffer, or a spaceship. A 3-glider collision that synthesises a R-pentomino via beehive works well, so guns and breeders have been constructed that fire spaceships and rakes of this speed respectively.

As for oscillators, there is a small period-32 reflectorless rotating oscillator called spinner, which gives banana sparks and is therefore capable of reflecting gliders by 90 degrees. Jason Summers found that a collision between a glider and a half-open twirling T-tetsons 2 produces two 90-degree gliders while sustaining the pre-pulsar engine, resulting in a period-60 glider gun; a blocker and a spinner can be added as filters for a p480 gun.

x = 21, y = 13, rule = B37/S23 8bo3bo$7bobobobo$8b2ob2o$b2o15b2o$o2bo13bo2bo$b3o13b3o2$b3o13b3o$o2bo 13bo2bo$b2o15b2o$8b2ob2o$7bobobobo$8bo3bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
The flower garden (click above to open LifeViewer)
RLE: here Plaintext: here

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


There is a proof sketch of DryLife's universality on ConwayLife.com forums. It is a proof-scheme covering all rules in the outer-totalistic rulespace between B3/S23 and B3678/S23678.[1]

In 2018, Peter Naszvadi constructed an explicit Rule 110 unit cell in DryLife, proving its Turing-completeness.[2] The pattern itself is basically a meta-polyglot, covering some related cellular automata in which the pattern only differs in some parts (in this case, the guns).


  1. Peter Naszvadi (December 12, 2016). Re: List of the Turing-complete totalistic life-like CA (discussion thread) at the ConwayLife.com forums
  2. Peter Naszvadi (March 29, 2018). Re: List of the Turing-complete totalistic life-like CA (discussion thread) at the ConwayLife.com forums

External links