7- Lost and Found Contour

This is where only part of an object is revealed by a sharp contour and the rest is represented by light.
This can also be described as now you see it- now you don't.

In this picture, only a few lines are given to create shape. The rest fade into darkness. Our eyes automatically fill in and follow the line even if it is not there, giving the illusion of a line, but then the line is picked up again by the changing of light. Therefore, the line is lost and found.