Ok so this first one popped into my head a couple of months back.. If you were to build a sealed cube made from one way glass, with the mirror sides all facing inwards, and you were to shine a light into the cube from the outside, once you take the light away, would it continue reflecting on the inside with no way of escaping? Also, if you were to have a light inside the cube, would any light be able to escape into a darkened room? Or would you just see a box of light that doesn't 'shine' past the edges of the cube? The other one is.. Can you have a space with solid sides that contains no oxygen? For example if you were to stand inside a completely solid and sealed box, that only had a small hole in one side, and then something like a vacuum was plugged into that hole and turned on to suck all of the air out, but not powerful enough to collapse the box, would you still be able to breathe?