I am not immune to flights of fancy, and came up with these ideas whilst wasting time on a summer's day. The sketch above depicts wind wheels driven by "prayer sails," which are of course prayer flags.
The sketch above depicts another wind-driven wheel, but with a difference. In addition to the mani wheel, this one also drives a resonating chamber buried beneath the ground. Six of these are tuned to produce the mantra, which resonates into the earth.
Above is a prayer buoy, which apart from being a hazard to shipping, is wind-driven and lives in the ocean.