Rules:
*You can teleport into and out of it at will
*It has a couple of plug sockets and can connect to internet from the region you teleported in from
*You can take objects and people with you
*As already stated, it is (3m)^3 (3m*3m*3m). The walls are plain plaster with a light in the middle of the ceiling. The pocket dimension is topologically toroidal, so if there weren’t walls and a ceiling/floor (which you can actually destroy) you would loop if you went more than 3m in any direction. Gravity, then, is artificial and can be altered to anywhere from 0 to 2g from a dial on the wall.
Edit: additional specifications
*You can only teleport out to where you teleported in from.
*Time proceeds at the same rate inside the pocket dimension
*There is an eject button for those inside to get out if something happens to you
Well, yes. We don’t know if the measurement we take is the result of a wave form collapse (we caused it) or the result of someone else having measured it, which would giving us the oposite value that they measured. We can’t tell if someone “sent” information or if it was the random result and we have no way to chose what value we (or the other end) gets when we collapse it.
This isn’t easy to explain over text so I’d recommend watching this video, specifically chapter “How to exploit?” as the visuals make it easier to understand.