It typically uses sets of optical prisms, or periscopically arranged mirrors to swap the view of the left eye with that of the right eye.
But the pseudoscopic inversion of a complicated picture — a landscape, streets, etc., produces a bewildering impression. It seems as if all the objects — men, trees, etc., had been placed in a depression of the earth, and yet everything remains in its place. Therefore, nearer objects appear very large, because we imagine them to be at a great distance, and more distant objects smaller, because they seem to be nearer.
The instrument subsequently fell into complete neglect for nearly two centuries. It was revived in 1852 by Charles Wheatstone, who published his ideas in his second great paper "On Binocular Vision," in the Philosophical Transactions for 1852. Wheatstone's paper stimulated the investigation of binocular vision and many variations of pseudoscopes were created, chief types being the mirror or the prismatic.
In 1853 the American scientist John Leonard Riddell (1807-1865) devised his binocular microscope, which contained the essentials of Wheatstone's pseudoscope.