ABSTRACT
The image on the left can be seen either as a black vase on a white background, or as two human profiles facing each other against a dark background. The image on the right can be seen either as a box on the floor or as the top corner of a room where the walls meet the ceiling. In both cases, you can flip your perception from one view to the other, reversing the figure that you see with everything else that is in the background, but it is very difficult not to see one as figure and the rest as ground.
