You guys do know that you don't really have to aim a mirror, right? It'll reflect anything you put in front of it. What you have to do is position the CAMERA so you can see what is being reflected in the mirror.

Student: Wait, wait professor! I once saw this movie where this man was in prison and the only way he could see what was outside his cage was to hold a mirror out the window and aim it.

Good point, Johnny. Yes, you can move any point around, but once again the mirror will show anything that is in front of it. It is only when the veiwer or camera is in the right position in relation to the mirror  that it will see what you want it to see.