1.1 ! anton 1: : fib ( n1 -- n2 ) ! 2: dup 2 < if ! 3: drop 1 ! 4: else ! 5: dup ! 6: 1- recurse ! 7: swap 2 - recurse ! 8: + ! 9: then ; ! 10: ! 11: : main 34 fib drop ;