Clock gears
Przemek Pietrak
CC BY-SA 3.0
Rods n Wires
Ben Salter from Wales
CC BY-SA 2.0
Science,_Technology_and_Engineering
Geralt
CC0 1.0
Gears
Steven Fine
Wheel_on_“Peggy,”_a_Lima_Shay_Geared_Steam_Locomotive_(SN_2172)
CC-BY-SA 4.0