!YS-v0

defn main(n=14):
  nums =: range().map(inc).map(str)
  rows =:
    loop row-n 1, nums nums, rows []:
      if rows.# < n:
        recur: row-n.++ nums.drop(row-n)
          conj(rows nums.take(row-n))
        else: rows
  width =: rows:last:last:len
  fmt =: \((' ' * (width - _:len)) + _)
  each row rows: say(row.map(fmt):joins)