1. A card adapted for use in a stereoscope that provides a three-dimensional image from two stereoscopically complementary images which are positioned substantially back to back relative to one another, said card comprising two stereoscopically complementary images each having an orientation, which images can be positioned, with the same orientation, substantially back to back relative to one another for viewing using said stereoscope, each of said images being viewable as a two-dimensional image independently of the complementary image and without employing the stereoscope, and wherein said two-dimensional images are not mirror images of each other.