What path does reflected light follow?

A smooth reflecting surface -- a mirror -- redirects light by a geometrical rule. In the picture below, the angle A between the incoming light beam and the mirror is the same as the angle B between the outgoing light beam and the mirror. the angles between the incoming light beam and the outgoing light beam are the same.

The result is that when the camera sees Cristina, Cristina can see the camera. Light travelling from Cristina to the camera (to make the photograph) and light travellng from the camera to Cristina (so that she can see the camera) take the same path in opposite directions.
    
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