The Wireworld computer

These pages describe how we went about building a Wireworld computer. Although at least one design exists for a tape-based Turing machine implemented in the ‘Game of Life’, ours is, as far as we know, the first ever computer implemented as a cellular automaton that you might reasonably want to write a program for. The design was done by David Moore and Mark Owen, with the help of many others, between 1990 and 1992. It’s a testament to our modesty that it was not until September 2004 that we wrote up our work.

You will need a browser capable or rendering looped animated GIFs to fully appreciate the pages that follow. Some of the image files are quite large.

This picture shows the display of the Wireworld computer as it calculates primes. The impatient reader will want to go straight to the last section below; those who prefer their gratification less instant can begin with the first.

• Introduction
• Signals
• The diode
• The OR gate
• The exclusive-OR gate (includes the ‘exclusive-OR gate joke’)
• The AND-NOT gate
• The ROM
• The flip-flop
• The binary adder
• The register bank
• The instruction set
• The final design

Experimental demonstration of the Wireworld computer in action, calculating primes. Java required.

Jeremy Sachs has implemented the Wireworld automaton in Flash. You can see it running the computer design here.

A modified version of the Wireworld computer which fits comfortably within an 800x600 rectangle in landscape orientation is available in the following formats:

• Static wallpaper which you can scale or centre as you wish;
• Precompiled xscreensaver code (x86 architecture, run e.g. as ./wireprimes -root -delay 10000 &) for use as animated wallpaper or as a screensaver (see http://www.jwz.org/xscreensaver/ for more information; source code available on request);
• PowerPC architecture xscreensaver code, kindly provided by Philipp Benner; I have not tested this version.