Unix on 41P7.2 is a period-42 oscillator composed of a unix and 41P7.2. Although it is composed of two oscillators of smaller periods (6 and 7 respectively), it is considered non-trivial because it contains a single cell that is alive in generation 13 and dead in the other 41 phases of the oscillator. In terms of its 57 cells, it was the smallest known non-trivial period 42 oscillator until the discovery of unix on 34P14 shuttle in 2018.
Generation 13 reveals the single cell that oscillates at the full period (in green).
- 57P42.1 at Heinrich Koenig's Game of Life Object Catalogs