These glasses allow the wearer to perceive two-dimensional images in three dimensions! Through selective refraction, the transparent lenses in the Chromadepth 3D Glasses change the perceived depth of different colors. Anything printed in the color red appears to move toward you and off the face of the paper (or screen). Blue appears to move back behind the paper. By selecting your colors carefully, it is possible to create an entire three dimensional image. Glasses work with an overhead projector, too! Package of 10.