In this brief video from the Cabinet of Physics, we see Morin's Machine demonstrate that uniform horizontal motion, combined with accelerated vertical motion, together trace a path with the form of a parabola.
Such motions describe many flying and falling objects, such as a projectile shot from a cannon or catapult. The smooth curve drawn by Morin's Machine may help a student visualize the connection between falling bodies and the algebra that generates parabolic curves.
The Foundation for Science and Technics, or Fondazione Scienza e Tecnica, of Florence, Italy, has made available many videos exploring the Cabinet of Physics, a large collection of antique scientific demonstration instruments. The Foundation's homepage may be found here, and its Youtube channel, florencefst, here.