Stone Prayer Wheel or Sutra Case. Cave 136, 1142-1146 AD. Beishan Grottoes, Dazu This fine carving in stone, redolent with dragon motifs from top to bottom, is designated as a "prayer wheel" by the label on site. It might also be described as a sutra storage case; the two ideas are compatible, since revolving a sutra case would be magically equivalent to reciting the sutras it contained. The stone carving is an elaborate imitation of a revolving wooden platform.