Gray counter is a period 4 oscillator that was found in 1971. The interior rotor simulates a cycle through the Gray codes from 0 to 3.
The 5-cell long sides of the main part of the stator require induction coils: the option with the smallest population (as well as the highest symmetry) uses two tubs as pictured. A smaller bounding box may be reached using snakes or bi-blocks.
A 27-glider synthesis is known for a stator variant of this oscillator in which one of the tubs is replaced with a boat.
- ↑ Adam P. Goucher. "xp4_wgiligz25a888a52zx256". Catagolue. Retrieved on May 24, 2019.
- 26P4.3 at Heinrich Koenig's Game of Life Object Catalogs