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
I would ask writers Game masters and gamers to use the item in their stories/games and see what uses they come up with i would never thought of on my own
Whike waiting for that to come to fruition ide look for a passable look a like to team up with.
Then i would figure out how the teleporting works. If it maintains speed/velocity/vector/momentum
test if i could jump from really high, pop into my pocket dimension just before hitting the ground cancelling out the speed i was falling when i pop out of the pocket dimension
If i can ill beat felix baumgartners records
If i cant then i would make use of the toroidal effect when popping in there after clearing the walls floor and ceiling. Longest free fall ever.
That record is now mine felix baumgartner!