Move the dot using the arrow keys at the start and when you are done press space. Then the light will travel towards the mirror and reflect away in a different direction depending on the original position of the dot. (The light ray is red to make it easier to see) The process may take a couple of seconds to complete.
A demonstration of real life physics that shows the reflection of light rays after hitting a mirror. All coding done by me @Solar-Powered . I decided to do this after doing the physics of light in science class in school. ENJOY!!!!!!!!!!!!!