[]
  5 times
    [ []
      5 times [ 20 random 1+ join ]
      nested join ]

  dup say "Array contains:" cr
  witheach
    [ witheach
        [ echo sp ]
      cr ]
  cr
  say "Array up to item = 20:" cr
  witheach
    [ false swap
      witheach
        [ dup 20 = iff
            [ drop not conclude ]
          else
            [ echo sp ] ]
      iff conclude
      else cr ]