Circute is a cellular automaton (and quite arguably an esoteric programming language) developed by Chris Pressey in 2005 as a test of the wire-crossing problem. It consists of nothing but logical NAND gates connected by wires. It was designed to be implementable in ALPACA.
- = - wire. Sparks pass through.
- - - tail, used to make sparks act more like snakes.
- # - spark. These spread across wires.
- N - NAND gate. If there's a free wire directly along the left or the right, send a message along any wire directly above or below.
Note: those marked with a * must be replaced with either a wire (=) or a spark(#). These just indicate where everything goes.
 AND gate
*== ==* = = ===N=== = = ===== = = =#N#= =
 OR gate
*== ==* = = ===== ===== = = = = ==N== ==N== = = ==#N#== = =
 One-fire switch(OSC->OFF)
===#N========= = = = ==N== ===== = = = = = = ===== ==N== = = = = * =====
 Tiny oscillator
Note: The tails mark the direction.
 Fast oscillator
=N# #N= =-----
Has a period of three steps.
 NOT gate
* = ===== = = ==N== = =
 Tiny NOT gate
* = =N# = =