How does vision work?
We see the observed body when the light falling on it enters our eye after reflection and an image of the body is formed on the retina of the eye.
How do physicists draw?
Physics diagrams eliminate everything that is irrelevant so that it is possible to focus on the properties of bodies or situations that are important for the natural phenomenon being studied. Such diagrams are very useful in understanding nature, but you have to learn to understand them.