P56 B-heptomino shuttle is a period 56 oscillator discovered in its original form (shown below) by David Buckingham sometime before May 1991, being the first period 56 oscillator to be found. It consists of a B-heptomino being hassled by two blockers and two blocks. In terms of its 45 cells, it is the smallest known period 56 oscillator. The blockers interact with the B twice, once to supress the block, and another time to prevent the formation of a Herschel.
8 reveals that the object being hassled is a B-heptomino.
- 45P56.1 at Heinrich Koenig's Game of Life Object Catalogs