The representation of shadows is used throughout the visual arts as a perceptual cue, suggesting the solidity of an object and providing a visual reference for the space it occupies.

What happens when a virtual object casts a virtual shadow onto a virtual surface? Do we still interpret the resulting image through the perceptual assumptions we bring from the physical world?

Here, the object that casts the shadow has been removed, leaving only the implied shadow. Deprived of its apparent source, the shadow becomes ambiguous: is it still a shadow, or has it become a diffused graphic object in its own right?