"The basic idea of the Virtual Window is that moving in front of a local video monitor causes a remote camera to move analogously, thus providing new information on the display (see Figure 1). To see something out of view to the right, for instance, the viewer need only "look around the corner" by moving to the left; to see something on a desk, he or she need only "look over the edge," and so forth. The result is that the monitor appears as a window rather than a flat screen, through which remote scenes may be explored visually in a natural and intuitive way. "
Reference: Gaver, W. W., Smets, G., Overbeeke, K. 1995 A Virtual Window On Media Space. In Proceedings of CHI'95
http://www.sigchi.org/chi95/proceedings/papers/wwg1bdy.htm