This document discusses light reflection off of plane mirrors and lenses. It describes two types of reflection - specular/regular reflection from smooth surfaces and diffuse/irregular reflection from rough surfaces. Mirrors can produce multiple images depending on their arrangement, with two mirrors at 90 degrees producing 3 images. There are two kinds of mirrors - concave mirrors that converge light rays and convex mirrors that diverge light rays. The mirror equation relates the focal length, object distance, and image distance.