An
extensible set of
period-4
oscillating,
moving shapes in the
game of life. They move at c/4 orthogonally, that is, one unit in an orthogonal direction every four generations.
The smallest three spaceships can stably exist alone:
lightweight middleweight heavyweight
spaceship spaceship spaceship
....... ........ .........
....... ...#.... ...##....
.#..#.. .#...#.. .#....#..
.....#. ......#. .......#.
.#...#. .#....#. .#.....#.
..####. ..#####. ..######.
....... ........ .........
The lone cells at the top of each spaceship, called sparks, die off and have no real effect on the progress of the spaceship; a spaceship without these becomes one with them within a cycle.
Longer spaceships, called overweight spaceships, must be escorted by small spaceships in order to prevent the creation of destructive sparks that do not decay quickly enough to prevent interaction with the spaceship.