So far, that's not surprising. What is maybe surprising is that B37/S23 is explosive even though B36/S23 and B38/S23 aren't. What's even more surprising is that adding

*more*birth conditions causes the rule to become stable. In particular, B357/S23 is stable. (A note on terminology: for the purpose of this post, "stable" means "eventually stable"; patterns may well show activity for a considerable number of generations, but will not generally grow without bound.)

So I wondered, given that we now have all the machinery to efficiently deal with non-totalistic rules (native support in Golly, Aidan's hacked version of apgsearch, and server-side support in Catagolue), what specific B5 subconditions are actually needed to tame B37/S23?

The subconditions that apply to B5 are a, c, e, i, j, k, n, q, r and y. Of these, e, j, n, q and r all immediately yield stable rules: B35e7/S23, B35j7/S23, B35n7/S23, B35q7/S23 and B35r7/S23.

What about a, c, i, k and y? They're not enough to stabilize the rule on their own, but I tried all possible combinations, with the following results:

Two subconditions:

- B5ac - explodes
- B5ai - explodes
- B5ak - explodes
- B5ay - looks stable, but explodes.
- B5ci - explodes
- B5ck - explodes
- B5cy - looks stable, but explodes.
- B5ik - explodes
- B5iy - stable
- B5ky - explodes, interesting patterns.

- B5aci - explodes
- B5ack - explodes
- B5acy - explodes
- B5aik - explodes
- B5aiy - looks stable, but explodes.
- B5aky - explodes
- B5cik - explodes
- B5ciy - explodes
- B5cky - explodes
- B5iky - looks stable, but explodes.

- B5acik - explodes
- B5aciy - explodes
- B5aiky - explodes
- B5acky - explodes
- B5ciky - explodes

- B5aciky - explodes

And while B35ky7/S23 is explosive and does not lend itself to being soup-searched, it's got an interesting very common puffer:

Code: Select all

```
x = 16, y = 9, rule = B35ky7/S23
b2o$o2bo$ob2o6bo$bo8bo$b2o2bo3bo3b3o$b2o3b2o7bo$3bo9bobo$6b4o3b2o$8bo!
```

Code: Select all

```
x = 20, y = 20, rule = B35ky7/S23
4obob4o5b4o$2ob4ob3o2b5obo$o3bo2b2o2bob3ob2o$2bo2bo2b2o2b3ob3o$ob2obob
6o2b4o$o6b2obo3b4o$3ob5ob2o4bo2bo$ob2obo2bo2b4o2bo$3ob3o9bo2bo$b3o2b4o
bob2o2b2o$3bob2ob2ob2obo2b2o$2b2ob2ob3ob8o$3bo2b2o2bo3bo$4b2ob5o2bo3b
2o$2o2b2o4bob4o$obob2o2bo2b2o5b2o$4o2b2o3bobo2b3o$3bo2bob2ob2o2b3o$ob
2o3b2o2b2ob4o$bo4bo2b3obobo!
```