Reflection Patterns of Laser Light on Tilted Mirrors

[Gregory.gags]

This may sound stupid, but why when I shine a laser pointer at a mirror and reflect in onto another mirror back and forth, the points of light make a parabola when the mirrors are tilted in such a way as to maximize the number of reflections happening? Tilting the mirror further or closer then causes the parabola to stretch or compress exponentially. Why is this?

 

[my_wan]

I don't follow what your actually observing when you say: "points of light make a parabola". Is this its path through the air, like what you would see with smoke or dust in the air?