A shadow is a dark shape, e.g. on the ground or a wall, caused by an object
or person, blocking light. Like a silhouette, the shape of the shadow is a two-dimensional projection of the
object.
For non-point sources of light, the shadow is divided into the umbra and
penumbra. The wider the light source, the more blurred the shadow. If there are multiple light sources there are multiple
shadows, with overlapping parts darker. For a person or object touching the
surface, like a person standing on the ground, or a pole in the ground, these converge at the point of
touch. |
