I was reading a novel in which one of the principle characters was sitting on a train waiting for it to leave the station. Abruptly the train appeared to move, but then the character realized it was the train opposite his window that was moving not the train he was on. Such changes in perspective are not uncommon, but always seem to evoke a little surprise. The Necker Cube, the skeletonized cube is used in introductory psychology courses to demonstrate that perception is...
