Figure eight (or less frequently, big beacon or lemniscate) is a period 8 oscillator found by Simon Norton in 1970. With 12 cells in its initial phase, it is the smallest known period 8 oscillator, behind blocker at 15 cells. It is known that no period 8 oscillators exist with 10 or fewer cells.
As a building block for larger oscillators
Because it produces a domino spark in one of its phases, it is useful for constructing larger oscillators that have period that is a multiple of eight. For example, it appears in tumbling T-tetson (period 8), sailboat (period 16), caterer on figure eight (the smallest period 24 oscillator), and figure eight on 36P22 (period 88).
As a reflector
Figure eight has the ability to act as a 90-degree glider reflector when it is combined with a block, boat and eater 1. The input path (in green) and output path (in red) of the glider are shown below.
Figure eight acting as a reflectorRLE: here
Figure eight is the tenth most common naturally-occurring oscillator in Achim Flammenkamp's census, being less common than the great on-off but more common than the spark coil. On Catagolue, it is the most common period 8 oscillator, being more common than blocker.
One of the phases of the oscillator, which led to both of its names.
- 12P8.1 at Heinrich Koenig's Game of Life Object Catalogs