(?:
    \1 (?:
      \2 \2 (??{ ".{" . 1.5*length($3) . "}" })
      $ (?{ print join(" ", map .5 * length, $1 x 2, $3 x 3, $2 x 4), "\n" })
      |
      \3 \3 (??{ ".{" . 1.5*length($2) . "}" })
      $ (?{ print join(" ", map .5 * length, $1 x 2, $2 x 3, $3 x 4), "\n" })
    )
  )