Back and forth of light - Fundamentals of Multiple reflection
When light reflects off a mirror, one image appears. Two mirrors placed exactly face to face give the appearance of an infinite number of images along a straight line. The multiple images seen between two mirrors that sit at an angle to each other lie over a circle.
Mirrors reflecting other mirrors
A mirror reflects everything in front of it including another mirror. If you place two mirrors at an angle, you increase the number of reflected images you can see. Depending on the angle you choose, you can see a number of unbroken reflections and one or more composite or partial reflections. When the mirrors are set at 90