Just looking at the story of fred, bob and emily.
And looking at it.
Bob punches a nail through the air in fred's safe.
So it appears to hang in mid-air.
It says that the walls of the safe are not damaged when the nail goes through.
But surely if Bob put a nail through Fred's world. the nail would extrude across the whole width of fred's world damaging the walls of fred's safe!
Or are we assuming that fred's safe has no side walls because his world is infinatly thin.
And it's saying the front, back, top and bottom walls of the safe aren't damaged.
It's probably me mis-interpreting it.
But just checking anyway.