The praying cylinders of Thibet. Buddhist prayer-wheels are rotating cylinders of varying size containing pieces of paper with prayers ('mantras') written or printed on them. The cylinders revolve clockwise; the direction of the sun's movement around the earth; and the prayers are supposed to ascend into the skies. The cylinders may be turned by hand; by turning a handle; or in the case of larger ones; by water; as seen in this view