Esoteric programming language – Wikipedia
Piet is an esoteric programming language in which the program code looks like an abstract painting. It was invented by David Morgan-Mar and named after Piet Mondrian, a pioneer of abstract art.
The sample program on the left outputs the word “Piet”. It is quite typical in its artificial look; Morgan-Mar’s goal was to approximate the look of common Mondrian images (right).
Like most other esoteric programming languages, Piet has no immediate practical use, but is treated in academic computer science education as an example of unusual language concepts.
Language concept of Piet
DM’s Esoteric Programming Languages – Piet (dangermouse.net)
The basic unit of Piet is a block of like color. Piet knows the following 20 colors here:
Program execution is controlled by black blocks and corners.
Numbers correspond to the number of pixels in the block.
Commands are defined by transitions of color and brightness: