I have been playing a game called Hexagonal 2048. Instead of hexagons, the game uses circles, but they are arranged in the same way as hexagons. After playing it for a while, everything on the computer seems rigid (as in menus and buttons) rather than smooth and rounded edges (even though nothing's changed). This has even carried over to things outside of the computer screen. I assume it's some sort of optical illusion as a result of looking at the circles for such a long time. Does anyone have any idea of what this phenomenon is called?