Still life (cellular automaton)

The term comes from the art world where a still life painting or photograph depicts an inanimate scene.

The distinction between the two is not always obvious, as a strict still life may have multiple connected components all of which are needed for its stability.

A random initial pattern will leave behind a great deal of debris, containing small oscillators and a large variety of still lifes.

A tub, a boat or a ship can be extended by adding a pair of live cells, to give a barge, a long-boat or a long-ship respectively.

A still life is called an eater when it can be used to absorb some other pattern (often a glider, spaceship, or the debris from a more complicated reaction) and returns to its original state after the collision.

Many examples exist, with the most notable being the fish-hook (Also known as eater 1), which is capable of absorbing several types of spaceship.

Oscillators with similar properties may also be called eaters or reflectors, but are more difficult to apply as they must be synchronized to the pattern they modify.

[4][5] The problem of fitting an n×n region with a maximally dense still life has attracted attention as a test case for constraint programming.