Step 1: Create a loop out of gearboxes with three axles between each two boxes but with one axle missing next to the gearbox receiving power from above.
Step 2: Add water-flow under the loop and attach a waterwheel.
Step 3: Close the loop.
Step 4: Remove the waterwheel and reuse it elsewhere.
Step 5: Attach any device of your choice to the loop and enjoy the miracle of infinite power.
Problem?