Visual representation of the domain and range of a function? An excerpt in the book "College Algebra by Michael Sullivan is that:

When the graph of a function is given, its domain may be viewed as the shadow created by the graph on the x- axis by vertical beams of light. Its range can be viewed as the shadow created by the graph on the y-axis by horizontal beams of light.

I did't get it and i also sought in google to get some idea but i can't find one.
Can anyone help me to understand it maybe with some graphics.
Thanks.

This is not meant to be difficult. It says that going perpendicularly down/up from each $(x,f(x))$ (parallel to $y $-axis) we reach the $x$ point (point of which $f(x) $ is the image).
So 'projecting' all $(x,f(x))$  onto the $x $-axis gives the domain.
And similarly for the 'shadow' on the $y$-axis.
