Piet



Piet is an esoteric programming language in which programs look like abstract paintings. It uses 20 colors, of which 18 are related cyclically through a lightness cycle and a hue cycle. A single stack is used for data storage, together with some unusual operations.

Piet was invented by David Morgan-Mar and is named after geometric abstract art pioneer Piet Mondrian.

Computational class
If the stack is allowed to hold any arbitrarily long number then it's Turing-complete. There is a Brainfuck interpreter in Piet, and since Brainfuck is Turing-complete, that makes Piet also Turing-complete.

External resources

 * Piet website
 * npiet - an interpreter and editor for Piet
 * PietDev - An online Piet editor and debugger
 * Dana Connell made 99 bottles of beer in Piet
 * Fizzbuzz in piet, produced using a code generator
 * A puzzle about a Piet, of which the solution is produced by a program in Piet. Created by hand.