IndexError

Level 1 of the Dungeon
(0, 0, D:1)
  a book of Burglary
(1, -3, D:1)
  a deep dwarf skeleton
(2, 0, D:1)
  a deep dwarf skeleton
(2, 2, D:1)
  a deep dwarf skeleton
(5, 2, D:1)
  a potion of enlightenment