// Wireworld
Posted on September, 11th 2021
While researching cellular automaton, I came across Wireworld, a two-dimensional four-colour cellular automaton created by Brian Silverman in 1987. Electrons move down wires which allows it to simulate transistors and logic gates and Wireworld is even Turing-complete, meaning it can create a computer capable of passing the Turing test. Click here to play around with Wireworld yourself.
## Tiles
There are four tiles each with their own rule:
- Empty (black)
- Electron head (blue)
- Electron tail (red)
- Conductor (yellow)
Time moves in steps, called 'ticks' or 'generations'. Every tick the cells check what they should change to:
- Empty → Empty
- Electron head → electron tail
- Electron tail → conductor
- Conductor → electron head if exactly one or two of the neighbouring cells are electron heads, otherwise remains conductor.
Wireworld uses what is called the Moore neighborhood, which means that in the rules above,
neighbouring means one
cell away in any direction.
These simple rules give the appearance of the electron head and tail moving down the conductor and
can be used
to create logic gates.
## Logic gates
In order from top to bottom are and OR gate, XOR gate and AND gate.
The other important gate is the diode (pictured below) which only allows electrons to go through in one direction.
Using these gates, people have been able to create 8 bit addition computers and 7 segment display. The most complex machine made so far, called the Wireworld Computer (wow how did you guess), can decode 64 bit numbers and show it denary.
## Controls
| Controls | Key(s) |
|---|---|
| Toggle play/pause | enter |
| Paint at cursor | space |
| Clear grid | x |
| Move left | ← or h |
| Move down | ↓ or j |
| Move up | ↑ or k |
| Move right | → or l |
| Selection mode | ctrk |
| Copy selection | y |
| Paste selection | p |
## Conclusion
Anyway, this was my first blog. It's taken a long time to put together this blog page because I've been so picky with how it looks. In the future, I am planning to add some more cellular automaton and show what cool stuff can be done with them but for now, I'll be signing out.
- Coloursplash