Transformation ratio is 3 (= n, number of Reuleax polygon sides). Two shafts are coaxial and rotate in different directions. Velocity of the output shaft is inconstant.
Theoretically, by increasing number of sides of a Reuleax polygon (7, 9, 11 …) it is possible to get large transformation ratio and make the output velocity less inconstant.
The mechanism has not been seen in practice and needs to be verified.