Awesome Self-Reference 
A curated list of examples of self-reference in art, science, and technology.
Contents
Art
- The Treachery of Images - A painting by René Magritte.
- Triple Self-Portrait - A painting by Norman Rockwell.
- Mise en abyme - A formal technique of placing a copy of an image within itself.
- Droste effect - The effect of a picture recursively appearing within itself, in a place where a similar picture would realistically be expected to appear.
Language
- Autogram - A sentence that describes itself in the sense of providing an inventory of its own characters.
- Fumblerule - A rule of language or linguistic style, humorously written in such a way that it breaks this rule.
- Recursive acronym - An acronym that refers to itself.
Mathematics
- Liar's paradox - This sentence is false.
- Russell's paradox - Does the set of all those sets that do not contain themselves contain itself?
- Trott's constant - The unique number whose digits equal its continued fraction coefficients.
- 13532385396179 - A number that is its own prime factorization, that is 13532385396179 = 13 × 53² × 3853 × 96179.
- Tupper's self-referential formula - A formula that visually represents itself when graphed at a specific location in the (x, y) plane.
- Life in Life - Conway's Game of Life running inside Conway's Game of Life using OTCA metapixels.
Computing
- Quine - A computer program that takes no input and produces a copy of its own source code as its only output.
- An Ouroboros Quine - A Ruby program that generates Rust program that generates Scala program that generates (through 128 languages in total) REXX program that generates the original Ruby code again.
- A radiation hardened quine - A Ruby quine that remains a quine after any one of the characters in its source code is removed.
- quinesnake - A quine that plays snake over its own source.
- The Qlobe - A Ruby quine with an ASCII image of a globe in its source code that rotates by 45 degrees after each run, eventually coming around after eight runs.
- html_wysiwyg - A truly naked, brutalist html quine.
- hashquine_by_retr0id.png - A PNG image of the ouroboros that displays its own MD5 hash.
- Meta-circular evaluator - An interpreter that defines each feature of the interpreted language using a similar facility of the interpreter's host language.
- A Micro-Manual for LISP - Not the whole truth - The LISP interpreter written in LISP.
- Fix-point combinator - A higher-order function fix that, for any function f that has an attractive fixed point, returns a fixed point x of that function.
- Universal Turing machine - A Turing machine that can simulate an arbitrary Turing machine on arbitrary input.
- Bootstrapping - A technique for producing a self-compiling compiler - that is, compiler (or assembler) written in the source programming language that it intends to compile.
- Man man - Manual pager man page (accessed using
$ man man).
Web
- Wikipedia - An article about Wikipedia on Wikipedia.
- Wayback Machine - Snapshots of The Internet Archive stored in The Internet Archive.
- Quine Tweet - A tweet that quote tweets itself.
- Awesome Self-Reference - A curated list of examples of self-reference in art, science, and technology, which includes itself.
Other
- Hofstadter's law - "It always takes longer than you expect, even when you take into account Hofstadter's Law".
- Miniatur Wunderland - The world's largest model railway in Hamburg, Germany has a model of itself in its model of Hamburg.
- Untitled Goose Game - The village where Untitled Goose Game takes place contains a small model version of itself, and also a tiny version of the model inside that.