Triple pseudo still life[1] is the smallest pseudo still life that can be decomposed into three stable subpatterns (shown below; note that the first and third are themselves pseudo still lifes), but cannot be decomposed into two stable subpatterns.[2] It was found by Gabriel Nivasch in July 2001. It consists of a single block surrounded by two hook with tails and two snakes.
Uniqueness
Nathaniel Johnston showed on May 25 2017, via an exhaustive computer search using Simon Ekström's still life searcher,
that the triple pseudo still life is the unique pseudo still life of 32 or fewer bits requiring a decomposition into 3 or more pieces.[3]
