I think it’s the shadow cast onto the largest round plate by the lower divided round plate
Without that shadow, the plates could be face-down and illuminated from the left, but the shadow would only exist if the light source is on the right, so it snaps everything to conform to that
For me it was a bottom small one that snapped them to right-way-up. With practice and effort I can flip them upside down again, and confirm that I don’t struggle seeing the big one as upside down, but still struggle with some of the bottom ones.
I think it’s the shadow cast onto the largest round plate by the lower divided round plate
Without that shadow, the plates could be face-down and illuminated from the left, but the shadow would only exist if the light source is on the right, so it snaps everything to conform to that
For me it was a bottom small one that snapped them to right-way-up. With practice and effort I can flip them upside down again, and confirm that I don’t struggle seeing the big one as upside down, but still struggle with some of the bottom ones.