Shared Silver Cup Award

From Draw Like da Vinci, p. 35: The human eye has difficulty  seeing the shape of a space when it lacks a boundary as a reference. When enclosed, the shape is easily recognised. The shape of the space around a face in profile may be difficult to grasp; however when a space is boxed in, its shape becomes obvious. The familiar example is the shape defined by two identical profiles facing one another. The mind’s eye alternates between seeing the outlines of two faces and the vase between them. 

When a boundary is repeated in a band, such as the frame of a window or the inner and outer contour of a toilet seat, the enclosed space becomes especially easy to recognise. The repetition of the outline reinforces the shape in our mind. The window is a favourite device of Leonardo da Vinci’s for framing portraits.