Gems is a Life-like cellular automaton in which dead cells are born if they have precisely three, four, five or seven live neighbors, and in which live cells will survive if they have precisely four, five, six or eight live neighbors. Small random initial configurations in Gems tend to turn into high-period oscillators (the "gems" the rule is named after); larger random initial configurations explode slowly.
No still lifes exist in Gems, and no odd period oscillators have been found in Gems.
Gems has a single known spaceship moving orthogonally at a speed of c/5648, David Eppstein's glider 13047. This is the slowest known elementary spaceship in any two-state outer-totalistic rule. It was also the slowest known across all two-state isotropic rules until it was surpassed by a c/5953 spaceship in the rule B2-an3acqry4cnw5-cj6cei78/S1c2n3-nqy4acknqtw5-ijkr6ei78, found by Arie Paap in July 2019.
|Glider 13047 (Catagolue: here)|
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RLE: here Plaintext: here
- Arie Paap (July 24, 2019). Re: Smallest Spaceships Supporting Specific Speeds (5s) Project (discussion thread) at the ConwayLife.com forums
- Gems: Long Live the Oscillators, and the Slowest Glider
- Gems at Adam P. Goucher's Catagolue
- Gems at David Eppstein's Glider Database