The Pi language is a public domain esoteric programming language idealized by Daniel Lopes Parra and invented by Marcelo Aires Caetano and Paulo Matias in 2006.
Pi is based on the brainfuck language and uses the same instructions as it. Pi works by calculating pi digits and introducing errors in some random digits of them, encoding obfuscated brainfuck instructions.
https:// esolangs.org/wiki/Pi
Brainfuck is the most famous esoteric programming language, and has inspired the creation of a host of other languages.
https:// esolangs.org/wiki/Brainfuck