On: x86 Quine: These 12 Bytes of Machine Code Print Themselves (2005)

[javajosh]

Why? Nothing is invariant under transformation in a quine.

[Sniffnoy → javajosh]

The code is a fixed point of a transformation, that transformation being "running it and extracting the output". Indeed, the fact that they always exist is a specialization of a more general fixed-point theorem! See: https://en.wikipedia.org/wiki/Kleene%27s_recursion_theorem