Knuth's up-arrow notation

(defun knuth (x n)
  (if (= n 2)
      (return-from knuth (expt x x))
    (return-from knuth (expt x (knuth x (- n 1))))
    )
)


Yes, an implementation in 6 lines of Lisp. What is Knuth's up-arrow notation? Wikipedia that shit. Don't try this with anything greater than (knuth 3 3), or you will overflow. (knut 3 3) == 3^3^3. (knuth 3 4) == 3^3^3^3.

These Factor snippets just keep convincing me that concatenative languages are full of fail. Can you obscure the intended meaning with stack shuffling any further?

Does anybody know of a concatenative language that isn't all about dup/swap/tuck/<stupid shuffleword here>? If it takes so much superfluous crap to gain any power, I'll achieve satori with a Lisp instead.