Input: the yellow shaft.
Output: the blue shaft.
Each shaft has a disk of torus groove.
Two orange rollers contacts with both disks.
Each roller rotates on its gear shaft. The gear shafts are connected together by a gear drive.
The contact pressure is created by the brown springs.
The input and output shafts rotate in opposite directions.
Turn the pink gear shaft to change contact position between the rollers and the two disks for various output velocities.