[ ' stack nested nested
    ' share nested join
    swap nested join
    dup dup 0 peek put ]   is recursive (   x --> x )

  [ over 2 < iff
      [ 2drop 1 ] done
    dip [ dup 1 - ] do * ] is factorial ( n x --> n )

  [ over 2 < iff drop done
    swap 1 - tuck 1 -
    over do dip do + ]     is fibonacci ( n x --> n )

  say "8 factorial = " 8 ' factorial recursive do echo cr
  say "8 fibonacci = " 8 ' fibonacci recursive do echo cr