Wireworld is a cellular automaton first proposed by Brian Silverman in 1987, as part of his program Phantom Fish Tank. It subsequently became more widely known as a result of an article in the "Computer Recreations" column of Scientific American.[1] Wireworld is particularly suited to simulating electronic logic elements, or "gates", and, despite the simplicity of the rules, Wireworld is Turing-complete.
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A Wireworld cell can be in one of four different states:
Software often numbers the states 0-3 rather than 1-4. In the examples given here, the states are displayed arbitrarily as colours proceeding through: black, blue, red, yellow.
Like in all cellular automata, time proceeds in discrete steps called generations (sometimes "gens" or "ticks"). Cells behave as follows:
Wireworld uses what is called the Moore neighborhood, which means that in the rules above, neighbouring means one cell away (range value of one) in any direction, both orthogonal and diagonal.
These simple rules can be used to construct logic gates (see below).
Entities built within Wireworld universes include a computer which enumerates prime numbers[2], and unit cells for another cellular automaton; Langton's Ant (allowing any Langton's Ant pattern to be built within Wireworld).[3]