- Wireworld
[
diode s, the above one in conduction direction, the lower one in reverse-biasing] Wireworld is a well-knowncellular 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 ". Wireworld is particularly suited to simulating electronic logic elements, or "gates", and, despite the simplicity of the rules, Wireworld isTuring-complete Fact|date=September 2008.Rules
A Wireworld cell can be in one of four different states:
# Empty
# Electron head
# Electron tail
# ConductorNote that in software these states are often numbered 0-3 rather than 1-4. In the examples on this page, the states are displayed as colours proceeding: black, blue, red, yellow. These colours are in no way standardized.
Like in all cellular automata time proceeds in discrete steps called generations (sometimes "gens" for short). Cells behave as follows:
* Empty → Empty
* Electron head → Electron tail
* Electron tail → Conductor
* Conductor → Electron head if exactly one or two of the neighbouring cells are electron heads and remains Conductor otherwise.Wireworld has 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 (orthogonal and diagonal).Using just these simple rules we can begin to construct gates (see below).
[
Clock generator s and anXOR gate ]Applications
Notable entities built within Wireworld universes include a computer which tests odd positive integers (and 2) for primeness [cite web | url=http://www.quinapalus.com/wi-index.html | title= The Wireworld Computer | author= Mark Owen] , and unit cells for another cellular automaton;
Langton's Ant (allowing any Langton's Ant pattern to be built within Wireworld). [cite web | url=http://www.heise.ws/wireworld.html | title= Wireworld | author= Nyles Heise]Computer programs featuring Wireworld
* [http://www.zillions-of-games.com/cgi-bin/zilligames/submissions.cgi/5295?do=show;id=2 Wireworlds] : the classical Wireworld cellular automaton and many variations. Game contains about 100 examples of logical gates etc created in Wireworld.
* [http://people.bath.ac.uk/amg24/ma10126/wireworld/simulator.html JavaScript Simulator] : a Wireworld simulation program
* [http://www.quinapalus.com/wi-index.html A Wireworld Computer] : an account of the construction of a full-scale computer using wireworld.
* [http://mirekw.com/ca/index.html MCell] : A free program for running cellular automata, can run Wireworlds.
* [http://docs.google.com/View?docid=d7htvkt_42gkzgp4] : Article about wireworld automata.ee also
*von Neumann's cellular automaton
References
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