Four boats (or hourglass) is a period 2 oscillator, which is composed of four boats in one of its phases. It has two diagonal on-off rotors enclosed by a common stator. While the two rotors are not connected, the stability of the stator still requires them to be in the same phase.
The on phase of this oscillator, the one which led to naming it four boats.
- ↑ Mark D. Niemiec. "Life objects sorted by name". Retrieved on April 30, 2009.
- 16P2.98 at Heinrich Koenig's Game of Life Object Catalogs