The water wheel turns a shaft with teeth that strikes the ends of these long poles that are connected to vertical pieces of wood that act as hammers. When the shaft engages the poles set on the fulcrum they are forced down at the end close to the water source. This in turn lifts the hammer in the air. Once the shaft tooth disengages from lifting the hammer up the teeth continue their revolution on the shaft causing the hammer to fall. This is repeated until the water is turned off. It is a simple machine.