Rotation transmission between two skew shafts with rope belt.
By moving the yellow bar it is possible to adjust angle between the shafts (from 0 to 360 deg.) and their axle distance.
The belt wraps 1 rev. around the blue pulley.
Two belt branches connecting to the pink pulley can be crossed to increase arc of contact or to reverse output direction.
To some extent it is a constant velocity joint.