Carter Bays wrote a paper "Candidates for the Game of Life in Three Dimensions" on that back in 1987 [1] and another in 2006 as mentioned on Wikipedia [2]: [1]

Carter Bays wrote a paper "Candidates for the Game of Life in Three Dimensions" on that back in 1987 [1] and another in 2006 as mentioned on Wikipedia [2]: [1] https://content.wolfram.com/sites/13/2018/02/01-3-1.pdf https://content.wolfram.com/sites/13/2018/02/01-3-1.pdf [2] https://en.wikipedia.org/wiki/3D_Lifex https://en.wikipedia.org/wiki/3D_Lifex