One is to be light like a bird, not like a feather.
Paul Valery

Rubin's vase is a graphic image based on the contrast between black and white fields, which creates a specific optical illusion. The white vase comes into view thanks to the contrast with a black background, while black contours become prominent owing to the white field which separates them. Optical phenomena on the topic of object-background appear exclusively due to the interaction of the two elements; if the vase disappears, the contours are also gone.