[ stack ]                              is comb.stack
  [ stack ]                              is comb.items
  [ stack ]                              is comb.required
  [ stack ]                              is comb.result

  [ 1 - comb.items put
    1+ comb.required put
    0 comb.stack put
    [] comb.result put
    [ comb.required share
      comb.stack size = if
        [ comb.result take
          comb.stack behead
          drop nested join
          comb.result put ]
      comb.stack take
      dup comb.items share
      = iff
          [ drop
            comb.stack size 1 > iff
              [ 1 comb.stack tally ] ]
            else
              [ dup comb.stack put
                1+ comb.stack put ]
             comb.stack size 1 = until ]
    comb.items release
    comb.required release
    comb.result take ]                   is comb ( n n --> )

  3 5 comb
  witheach [ witheach [ echo sp ] cr ]