An OCaml -> Haskell -> OCaml Ouroboros Quine
$ ocaml ouroboros.ml > ouroboros.hs
$ ghc ouroboros.hs
$ ./ouroboros > ouroboros_again.ml
$ diff ouruboros.ml ouroboros_again.ml
$ echo $?
0
This is an OCaml program that outputs a Haskell program which outputs the original Ocaml program.
Here are some hints if you'd like to try this yourself, but are getting stuck. There are other ways to do this without using these hints though.
Hint 1 (Ocaml)
Printf.printf "%S" "hello \"world\""
Hint 2 (Haskell)
putStrLn $ show "hello \"world\""