Example of a paddle boat using three interacting rotating magnets (red arrows) as a drive. Two magnets are connected to the paddles and one to the driver. If the driver magnet is rotated, the paddles move accordingly (yellow arrows).
Magnetic gears transmit rotary motion like mechanical gears but instead of teeth they use magnetic attraction and repulsion between rotating magnets. Magnetic gears have several advantages over mechanical gears. The main one is the absence of direct contact between the parts.

A new method of constructing magnetic gears positions the input and output axes at any desired inclination angle. In addition, there are certain configurations of the two magnets that allow the addition of a third magnet at a specific position while still maintaining a smooth coupling.

Source