Well never really. I did point out that almost all plane windows are made by the same company. There can’t be a curve left to right or else if you followed that curve with your eyes where would it start or end. So the way our eyes work, even a Flat horizon like at the beach has to taper in at the ends. Think of it this way... we are the center of a circle of view so our view is always a radius. Meaning you can see equal distance in all directions which makes it a circle whether we are on a plane or a ball.