HighLife

The evolution of the replicator

HighLife is a cellular automaton similar to Conway's Game of Life. It was devised in 1994 by Nathan Thompson. It is a two-dimensional, two-state cellular automaton in the "Life family" and is described by the rule B36/S23; that is, a cell is born if it has 3 or 6 neighbors and survives if it has 2 or 3 neighbors. Because the rules of HighLife and Conway's Life (rule B3/S23) are similar, many simple patterns in Conway's Life function identically in HighLife. More complicated engineered patterns for one rule, though, typically do not work in the other rule.

The replicator

The main reason for interest in HighLife comes from the existence of a pattern called the replicator. After running the replicator for twelve generations, the result is two replicators. The replicators will repeatedly reproduce themselves, all on a diagonal line. Whenever two replicators try to expand into each other, the pattern in the middle simply vanishes. Replicators can be used to engineer other more complex patterns, such as glider guns and high period oscillators.

In Conway's Life, it has been proven that replicators exist, but no explicit construction for one is known.

External links

• Life lexicon: replicator
• HighLife - An Interesting Variant of Life (ZIP file of a single text file)