Thanks for this, it brings back memories. I did a similar search of rules way back when but much less systematic. HighLife and Day and Night were two rules tha

Thanks for this, it brings back memories. I did a similar search of rules way back when but much less systematic. HighLife and Day and Night were two rules that I found and shared with a private mailing list that Conway was on. He was very complementary as I recall, I was elated. Day and Night came from a deliberate search of the subset of rules that were self-inverse. For example the inverse of Life is a rule where the background is normally black and objects are white. But some rules have a symmetry where objects exist as well as their inverse. Likewise HighLife came from a search of rules that supported the Life glider - there’s a subset of neighborhoods that aren’t involved in the glider evolution and can be set to other values. I noticed HighLife because it has a naturally occurring replicator, something very rare.