Task

Draw a Cantor set.



See details at this Wikipedia webpage:   Cantor set

  [ $ "" swap witheach 
      [ nested quackery join ] ] is expand (   $ --> $ )
 
  [ $ "ABA" ]                    is A      (   $ --> $ )
 
  [ $ "BBB" ]                    is B      (   $ --> $ )
 
  [ char A = iff
      [ char q ] else space
    swap of echo$ ]              is draw   ( n c --> $ )
 
  81 $ "A"
  5 times
    [ dup witheach
        [ dip over draw ]
      cr
      i if
        [ expand
          dip [ 3 / ] ] ]
  2drop
 