The Graphic Arts Collection has a large collection of magic lantern slides but only a few mechanical or movable slides. We have some chromotrope slides with cranks or pulleys that produce abstract geometrical patterns and colors. Others have two or three sheets of glass that slide back and forth to conceal and reveal parts of a scene. These are known as slip-slides. Some are meant to be snapped, creating a sudden appearance, while others move slowly, dissolving from one view to another.
Here are a few animated GIFs of our slipping slides.