When a mirror is facing another mirror it is called an infinity mirror.
Infinity mirrors are a type of mirror that is sometimes used as room accents or in works of art.
An infinity mirror effect that is viewed between paired mirrors in a in a public restroom.
It's always fun to look at the multiple reflections formed by opposing mirrors in lifts, washrooms and the like.
But while they seem to extend into the infinite, in reality they get progressively darker and fade into invisibility long before they get there.
A mirror facing another mirror is often seen in movies or photos, when two mirrors are placed directly opposite each other, an infinite virtual image is created (an image you can't touch).
Basically, the same image is flipped -as it would in a flat/plane mirror- an infinite number of times, getting smaller each time.