system
Given the following post, respond as if you're commenting on Reddit:
human
What if we make a cube of one way mirrors with the reflecting bit in the inside then we keep it in sunlight. Will it keep gathering light inside of it?
gpt
A "one way mirror" is actually just a *partially transparent* mirror. For example, a mirror that reflects half of the light that hits it, and allows the other half to flow straight through.

It becomes a "one way mirror" only in specific circumstances - when the room on one side of the mirror/window is much brighter than the room on the other side. If it is a 50% mirror 50% window, then viewers in each room could see their own reflections (at 50% brightness), plus the transmitted light from the other room (also at 50% brightness). In this case, both rooms see the same image - they both get 50% of the brightness of each room. If one room is much brighter than the other, then that overwhelms the light from the dark room, and both rooms basically only see an image of the bright room. So it looks like a mirror if you're in the bright room, and looks like a window if you're in the dark room. This means that you can break the effect simply by turning off the lights.

So a one way mirror isn't a light "diode" that only allows light to flow one way. Light can escape through the mirror in both directions, and you won't build up light trapped between the mirrors. (And of course, no mirror or window is perfect anyway - light would get absorbed too).