Split-screen stereography was discovered not long after the invention of photography, like the popular stereograph viewer from 1876 shown in the following picture (B.W. Kilborn & Co, Littleton, New Hampshire; see http://en.wikipedia.org/wiki/Benjamin_W._Kilburn). A stereo photograph has separate views for the left and right eyes, which are slightly offset to create parallax. This fools the brain into thinking that it's a truly three-dimensional view. The device contains separate lenses for each eye, which let you easily focus on the photo close up:
Similarly, rendering these side-by-side stereo views is the first job ...
