Goblet illusion This image is simultaneously a drawing of a goblet and two faces When there are two competing interpretations of an ambiguous image the brain will often switch between them So a viewer of this image which has been around in some form since the th century may see a white goblet for a while but then change to seeing two black faces in profile It is impossible to see both at the same time It is also impossible to view this as abstract shapes once the brain knows the form of a goblet and of a face in profile it must assign one of the two to its interpretation of this image