Efficiency

Level 5 of the Dungeon
(0, 0, D:5)
  a stone
(0, 3, D:5)
  a stone
(1, 0, D:5)
  a stone
(2, 2, D:5)
  4 large rocks
(4, 1, D:5)
  a stone
(5, 3, D:5)
  a stone
(5, 14, D:5)
  a scroll of identify
(11, 10, D:5)
  11 stones
(14, -3, D:5)
  18 gold pieces

Level 6 of the Dungeon
(0, 0, D:6)
  15 gold pieces