The question now is: I can see the treasures hidden by two-dimensional people in their "impenetrable" safes, but what would a four-dimensional being see when looking at my safe?
To discuss the issue of how a four-dimensional being perceives the box where we hide treasures, I think it can be explained using the concept of "boundaries." A point drawn on a one-dimensional line divides the line into left and right, but such a boundary does not exist for two dimensions. Simply put, if there's a utility pole blocking your way on the road, you wouldn't be stuck, because you can go around it. In two-dimensional space, drawing a circle divides the plane into inside and outside the circle, but this kind of boundary is not a restriction for three-dimensional beings; through the third dimension, inside the circle becomes the same as outside the circle—otherwise, no one would dare to play with hula hoops. Now, if we look at a three-dimensional safe that I create, it divides space into inside and outside the box. We can infer that such a limitation would not exist for four-dimensional beings either; through the fourth dimension, inside the box is the same as outside the box.