Over the years hundreds of educational sets were marketed to teach geography, social studies, science, history and reading. They even produced and sold a special line of stereoview sets for medical students. Lantern slides and stereoviews were often combined in sets, with one side of a stereoview printed on glass so that a two-dimensional image could be projected on a screen for the entire class to see. Students could then take turns viewing the three-dimensional version of the photos with the stereoviews and one of the many stereoscopes that came with the set.