In this Demonstration, a roller drive is simulated by two curves rolling along each other without slipping. The curve on the left is the driving roller and turns at a constant angular speed. The curve on the right is the driven roller and turns at an angular speed proportional to the ratio between the radii of both rollers at their contact point.
Controlling the parameters to , you can vary the cumulative angular displacement curve of the driven roller. These parameters can also be used to compute the equivalent polar curves of both rollers.