Temporary See Through Mirror
A mirror's make up is very simple. It is a plane of glass then a layer of silver nitrate then a black backing to keep the silver nitrate reflective at all times. If we remove the black backing and keep the pane of glass and the silver nitrate, you can see right through it. If we have a light that we can turn off and on on the inside of something like a medicine cabinet (behind the mirror) or anything else and we keep the glass and silver nitrate but drop the black backing, we could shut the cabinet door with the light out on the inside of the cabinet and the darkness would serve to reflect your image just as well as the black backing (both being a black backing). But we then have the option of not having to open any doors or cabinets, since we can turn the inner light on and see what's inside by illuminating the back of the silver nitrate we see clearly through and past it and we can then know what's inside with no effort. This could be applied where any mirror or glass is used. A novel sounding idea, but (I think) very applicable in many instances and situations! This is not a two way mirror.
Reward: A very large mirror installed in my bathroom and a same size cabinet! I plan on stocking up on tooth paste!