Useful Notes / Stereoscopic Imagery
Stereoscopic images have been around since photography was invented, and they haven't changed much since then. It's very simple, shoot two images side by side, then use a technique to show both of them to the viewer so he or she can notice the depth. The primary way to do this is to stack the two photos in a device that lets the viewer see each image individually with each one of his eyes. It can be a pair of glasses, or a box.