The Magic of a Windmill

Some mills run on water, a giant wheel turned by the flow of a river. Ours is old, hundreds of years old, and still in solid working order. A sluice gate is lifted, somewhere on higher ground, and water comes rushing down a canal to fill the bucket sections along the diameter of the wheel. Once three or four are full, the weight of the water pulls the wheel forward, and it begins to turn until it is spinning powerfully.