Paradoxical gears both rotate in the same direction.(e.g. both clock-wise) Normally gears rotate in opposite directions, meaning the gear on the left rotates c

Paradoxical gears both rotate in the same direction.(e.g. both clock-wise) Normally gears rotate in opposite directions, meaning the gear on the left rotates counterclockwise and the gear on the right rotates clockwise(or vice-versa). It just so happens that any paradoxical gear has to be "3D"(no 2D solution), there are "normal" gears that are 3D though.