Stereoscopic Photography
Stereoscopic, or 3D photography, works because it is able to
recreate the illusion of depth. Human eyes are set some
distance apart, so each eye sees an image slightly differently.
If one takes two separate photographs that same distance
apart, with a suitable viewer it is possible to recreate that
illusion of depth.
Binocular drawings were made by Giovanni Battista della
Porta (1538-1615), which clearly indicated his understanding
of binocular vision.
In 1613 the Jesuit Francois d'Aguillion (1567-1617), in his
treatise, coined the word "stereoscopique"