supertux/data/images/worldmap/common/n_stone.sprite

(supertux-sprite
  (action
    (name "default")
    (hitbox 16 16 0 0)
    (images "n_stone.png")
  )
  (action
    (name "solved")
    (hitbox 16 16 0 0)
    (images "n_stone.png")
  )
)