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.
Producing a domino spark, it is useful for constructing larger oscillators with 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). It is also the key component in the p8 bouncer.
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