Rotational to Linear Motion

I found the "Multiple Straight Line Drive" very interesting out of the mechanisms on the site. It takes the rotation of a large disk and ends with a piston moving up and down. The small gear spins faster than the disk because of the teeth around the edge, and the small gear itself, while rotating, moves in a circle. Because the small gear has half the diameter of the disk, its edge is always at the center of the disk. The piston attaches to the small gear so that it is tangent to the small gear, and the piston moves up and down while the side-to-side motion of the gear is compensated by the arm between the piston and the center of the small gear. Therefore, the piston follows the up-and-down motion of the gear but not the side-to-side motion, changing rotational to linear motion. I especially liked this mechanism because it is able to create a constant motion without sudden changes in speed, which some other mechanisms had.