Three-dimensional viewing works by making each eye see an image from a slightly different perspective, as we do when viewing real-life objects. Glasses make this easy, as they can filter out two simultaneously projected images so that each eye sees only one. But glasses-free 3D has been a goal of TV and mobile developers for a while now, because wearing 3D glasses at home is annoying, and relying on glasses to view 3D images on your tablet or cellphone would be downright ridiculous.
