Non-point Source
For a non-point source of light, the shadow is divided into the umbra and penumbra. The wider the light source, the more blurred the shadow. If two penumbras overlap, the shadows appear to attract and merge. This is known as the Shadow Blister Effect.
If there are multiple light sources there are multiple shadows, with overlapping parts darker, or a combination of colors. 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.
Read more about this topic: Shadow
Famous quotes containing the word source:
“Man is a stream whose source is hidden. Our being is descending into us from we know not whence. The most exact calculator has no prescience that somewhat incalculable may not balk the very next moment. I am constrained every moment to acknowledge a higher origin for events than the will I call mine.”
—Ralph Waldo Emerson (1803–1882)