You can turn a window into a one way mirror by installing a dark or dual reflective film on the glass.
The dual reflective film can be as much as 40 percent more reflective on one side when compared to the other side.
Being dark also allows less light transmission from one side to the other side.
Places you should not put mirrors are in front of a bed, on the ceiling, at seated eye level in a dining room, opposite a shower or behind a toilet, above a tall fireplace, opposite a window that lets in very bright light or above the bed.
The endless mirror effect is also known as the infinity mirror which is a configuration of 2 or more angled or parallel mirrors that are arranged in order to create a series of smaller and smaller reflections which appear to recede to infinity.
A half mirror is a reciprocal mirror which appears reflective from one side and transparent from the other side.
A half mirror is also known as a one way mirror which has a thin reflective coating called a half silvered surface and the surface makes the glass translucent and only reflect about half the light that strikes it's surface.
When you point two mirrors at each other or put a mirror in front of a mirror an infinite virtual image will be created which is an image you cannot touch.
The same image is basically flipped as it would be in a flat/plane mirror and for an infinite number of times while getting smaller each time.
Mirrors facing each other create what's known as an "infinity mirror" effect.
The infinity mirror effect is a series of reflections that appear to go on forever.
It can be super trippy to look at and a cool trick of optics, but it's not a gateway to the netherworld.
When you have two mirrors across from each other, they are streaming energy back and forth between them.
This is definitely something you do not want if they are placed in an area that you sit or sleep between.
This is way too much energy for a relaxing or peaceful space.
If you place two mirrors facing each other in a dark room, legend says you have created a ghost portal through which spirits can pass.