Reminds me of a fun trick that was popular when I was in undergraduate mechanical engineering: A gear train that has one end spinning, powered by a small DC motor, and one end bolted/welded/glued/otherwise fixed solidly to a wall.
Increase the ratio enough and you can have an output shaft that will take years to go through even a fraction of a revolution ;)
Increase the ratio enough and you can have an output shaft that will take years to go through even a fraction of a revolution ;)