Try some of these circuits
or click squares of the grid to construct your own.

  A simple clock  
  A frequency halver  
  A diode  
  A   NOT gate  
  An OR gate  
  An XOR gate  
  An AND gate  
  A   NAND gate  

 

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A clock emits regular impulses without receiving any input.

Clocks can have different frequencies: this one delivers an impuls every 4th time step.

A frequency halver just does what it's name says: it only lets pass one out of two signals.

Karl Sherer first published this particular circuit in September 2003.

A diode blocks a flow of electrons, but only in one direction.

This circuit shows a clock, sending impulses to 2 diodes. The upper one lets the flow pass,the lower one blocks the flow.

A NOT gate emits an impulse if there is no impulse on its input.

An OR gate emits an impulse if there is an impulse on one or both of the inputs.

An XOR or exclusive OR gate emits an impulse if there is an impulse on one and only one of the inputs.

An AND gate emits an impulse if there is an impulse on both of its inputs.

A NAND gate is the combination of an AND gate with a NOT gate.

WireWorld is, just as Conway's Life, a cellular automaton. It is the brainchild of Brain Silverman, to whom we also own Brian's Brain, another very interesting cellular automaton. He published the first version of WireWorld in his programme "Phantom Fish Tank" in 1987. Just as Martin Gardner devoted one of his columns to Life, A. K. Dewdney publicised WireWorld in January 1990 in his "Computer Recreations" column in Scientific American, thus contributing largely to its popularity.

Like all cellular automata, WireWorld is composed of coloured square cells, laid out on a rectangular grid and a simple set of rules describing the changes that can occur.

While Conway's Life can be rather chaotic with cells moving all over the grid, WireWorld is more static. As the rules do not allow static ("background") cells to become active, the three types of active cells can only change their colour and do not move all over the grid.

But the most interesting characteristic of Wireworld is that it is especially adapted to simulate the behaviour of electronic and logical circuits. Given a very large grid, it is possible to simulate a computer (see the  More Information  section for an example). For the time being, making the smallest possible simulations of binary additions and multiplications is one of the fields of investigation in this fascinating world. But even that is way beyond the scope of this limited (due to the lack of execution speed of JavScript) demonstration, that will only show you some very basic circuits.

If this demonstration could sharpen your appetite to gather more information about WireWorld and cellular automata, it would already have reached its goals.

• A checkerboard represents the world. This world is limited here to a 40 by 40 grid.
  
  
• A cell can be in one of four different states:
  
  
  • background (  ),
    
    
  • wire (  ),
    
    
  • electron head (  ),
    
    
  • or electron tail (  ).
    
    
• Each cell of this grid has 8 neighbours.
  
  
• The evolution of the cells is determined by four simple rules:
  
  
  • a background cell always remains a background cell ( stays )
    
    
  • an electron head always changes to an electron tail at the next time step ( becomes )
    
    
  • an electron tail always changes to a wire at the next time step ( becomes )
    
    
  • a wire changes to an electron head at the next time step if one or two of its neighbours are electron heads ( becomes  if one or two neighbours are )
    
    
• Changes occur simultaneously: they are unaffected by other changes that occur at the same time step.

• The Virtual Computer by Brian Silverman can be consulted on the net.
  
  
• Mark Owen describes a simple computer made with WireWorld.
  
  
• For more information and links, consult the pages of Nyles Heise.
  
  
• Ed Pegg, a collaborator of Wolfram Research, also offers some background information
  
  
• The site of Wolfram Research offers also a very good bibliography about cellular automata.
  
  
• Alternatively, you could also take a look at the pages devoted to Math Games by The Mathematical Association of America.
  
  
• Mirek Wojtowicz's site offers tons of information about cellular automata.
  
  
• And Mirek also offers an exhaustive survey of diferent rules for cellular automata.