tjhance

There is a general theorem that says that for any computation, you can write a program that executes that computation on its own source code. The quine is only a special case.

Actually I think the 'ace' in Paper/Hackpad/Etherpad is a different thing called ace.

www.scottaaronson.com/papers/ctc.pdf

Shows that (with or without quantum computing) you can do all of PSPACE using a CTC (in polynomial time) and no more.