Pseudoscope

Pseudoscope (Gr. pseudēs, 'false,' and skopeō, 'I see'), an optical instrument through which, by means of an arrangement of prisms, objects are seen with their relief inverted. What is convex appears concave, and a figure in intaglio appears to be cut in relief. It was discovered by Wheatstone when experimenting on the Stereoscope (q.v.).