Sea Slugs (B2-a5678/S014567)
Posted: April 12th, 2026, 2:22 am
EDIT: Fixed thread title - I had been playing with multiple rules at the time and got mixed up. The correct rule has S0.
Sea Slugs (B2-a5678/S014567) is a nearly-outer-totalistic rule, with the only exception being that birth on two adjacent neighbours is specifically forbidden. I decided to have a look at rules around Rings 'n' Slugs with B2-a birth conditions to try to find one with spaceships, and found this rule as a result. This rule keeps the titular ring and slug still lifes from its precursor. These structures are quite resistant to collapse, which should make finding catalysts a lot easier.
The star of the rule, as well as the 3rd most common object from asymmetric soup, is this 3-cell 3c/10 orthogonal spaceship:
There are also far less common but not vanishingly rare c/2 spaceships (and a bonus derived wickstretcher):
Linear growth is quite common, occuring in over 1% of 16x16 soups. Here are the top 5 most common linear growth patterns by decreasing frequency:
The common engines are low period and infrequent enough that apgsearching mostly runs smoothly. There are also higher period c/2 puffers as well.
The thing that apgsearch sometimes gets stuck on is a certain type of pattern where a wickstretcher is attacked by a chaotic sawtooth-like signal:
The signal eventually destroys the frontend and rips the wick apart irregularly, and it seems like apgsearch eventually just classes it as zz_LINEAR after running it for a long time. In certain cases like the provided pattern, the destruction happens so late and burns for so long that there are more wickstretchers that get spawned from the ash and burned as well, seemingly endlessly. Under some definitions, this rule could be considered explosive, but in such a way that small patterns are relatively safe from the behaviour.
3c/10 eaters:
As a demonstration of how strong the catalysis potential in this rule is, here's a slug (violin?) that reflects every second 3c/10 over the diagonal axis:
And also a... synthesis component?:
Sea Slugs (B2-a5678/S014567) is a nearly-outer-totalistic rule, with the only exception being that birth on two adjacent neighbours is specifically forbidden. I decided to have a look at rules around Rings 'n' Slugs with B2-a birth conditions to try to find one with spaceships, and found this rule as a result. This rule keeps the titular ring and slug still lifes from its precursor. These structures are quite resistant to collapse, which should make finding catalysts a lot easier.
The star of the rule, as well as the 3rd most common object from asymmetric soup, is this 3-cell 3c/10 orthogonal spaceship:
Code: Select all
x = 2, y = 3, rule = B2-a5678/S014567
2o2$bo!
Code: Select all
x = 9, y = 22, rule = B2-a5678/S014567
2bo$3b3o$2b5o$ob5o$b4o$o3$2bo$3b3o$2b6o$ob5o$b4o$o3$2bo$3b3o2bo$2b6o$o
b6o$b4o3bo$o!
- Growing spaceship, frontend c/3 diagonal, backend c/4 diagonal
- c/7 wickstretcher
- c/3 diagonal wickstretcher
- Two-cell tagalong for growing spaceship #1
- Combined c/7 and c/3 diagonal wickstretchers
Code: Select all
x = 86, y = 7, rule = B2-a5678/S014567
3o18bo18bo20bo19bo$5o15bobo18b3o16bo2bo16b3o2bo$b3o16b3o18b5o16b3o16bo
bo$4bo15b3o19b3o17b5o$2bo18b2o22bo17b3o16bobo$21b2o20bo22bo16bo$20bo2b
o40bo!
The thing that apgsearch sometimes gets stuck on is a certain type of pattern where a wickstretcher is attacked by a chaotic sawtooth-like signal:
Code: Select all
x = 7, y = 10, rule = B2-a5678/S014567
4bo$2b2o$b3o$2obo$2obo$b4o$2b3obo$3b2obo$5bo$4bo!
3c/10 eaters:
Code: Select all
x = 44, y = 7, rule = B2-a5678/S014567
39bo$40b2o$8bo31b3o$41b2o$2o28b2o11bo2$bo29bo!
Code: Select all
x = 61, y = 8, rule = B2-a5678/S014567
54bo$55b2o$55b3o$56b3o$2b2o53b3o$bo2bo11bobo11bobo12b2o11b2o$bo14b2o
42bo$3obo10bo2bo12b2o13bo!
Code: Select all
x = 17, y = 8, rule = B2-a5678/S014567
10bo2bo$11b2o$11b2o$11b3o$2o9b4o$12b4o$bo11b3o$16bo!