[FranchuFranchu]

Note: This just says that any GoL pattern that can be constructed by a universal constructor can be constructed from 15 gliders. A universal constructor is a GoL pattern that can construct a very diverse set of patterns, but not any pattern. For example, Garden of Eden patterns are excluded from this category.

[andrewla]

> For example, Garden of Eden patterns are excluded from this category.

That seems to be naturally true, since they by definition cannot be constructed. Are there other patterns that cannot be constructed by a universal constructor, or are all such patterns non-constructible?

[biggiemac42]

The post (and my previous waterbear post) both talk about universal construction, it is equivalent to glider construction. There are patterns which have N generations of predecessor but not N+1, which are also non-constructible.