What I find interesting is that if you turn the design a certain way you get a whole different image perception.
The first image looks to me like a big box corner with a smaller box inside it.
The second image looks like a big box with a small box piece missing.
If you can't see the differences, then maybe the images are too big---step away from the screen, or squint at the images.
I understand that some people cannot see three-dimensionally very well. My new husband and I just went to the 3-D movie, 'Gravity' last night. Jerry claims that it's a waste of money for him, that he can't see the dimensionality of it anyway.