I saw this guy who claims that how you see the center as a bump of indentation reflects how your brain was wired when you first learned how to write, I just wanted to see if that is true. I mean… it seems like it might be a thing.
No as the red lines can go in or out too they just follow what ever shape, I just opened it on my phone so I could turn it upside down, they still change but then it gets freaky when I rotate it back and forth.
The best way I can describe it is as a button sticking out of the floor and one sticking out of the ceiling. Then becoming a hole in the floor and a hole in the ceiling, if that makes any sense to you.
What I mean is that the positive gradient, straight bit, then negative gradient in the 2D depiction of the “convex” shape seems to force the central region to be perceived as sticking out of the plane (i.e., closer to the viewer) when interpreted as a 3D object, and vice versa for the “concave” shape. I think perceiving the central region of the “convex” shape as going into the plane would cause a discrepancy between how the line is interpreted and how the hexagon is interpreted (i.e., they’d have to be interpreted as being viewed from different angles to make sense). At least to me…