A shadow theater was originally a three-dimensional assemblage, often made with paper or cloth, designed to be backlit to depict a scene. Related to Victorian "paper theaters," it's a kind of diorama.
These shadow theaters can be cut from paper, folded, and assembled. They can also be cut from thicker stock like wood or acrylic and glued together to create the scene. They can even be cut from different colors of paper and stacked to make a thinner, almost two-dimensional version.
