Spaceship (cellular automaton)

In a cellular automaton, a finite pattern is called a spaceship if it reappears after a certain number of generations in the same orientation but in a different position.

The smallest such number of generations is called the period of the spaceship.

More generally, if a spaceship in a 2D automaton with the Moore neighborhood is translated by

is defined as: This notation can be readily generalised to cellular automata with dimensionality other than two.

In March 2016, the unexpected discovery of a small but high-period spaceship enthused the Game of Life community.

[1] A similar example,[2] called "loafer", was found a few years earlier.

In March 2018, the first elementary spaceship with displacement (2,1) (knightwise) was discovered and named Sir Robin.