Interesting idea. I’m eating lunch and my chin is approximately 90 degrees perpendicular to the flat level table. As I look to the far edge, the perimeter edge is clearly curved but it is at a 45 degree angle to my chin. A penny under my face looks round but the one across the table looks oval. So the assumption that all angles are same is provable and measurable false
Interesting idea. I’m eating lunch and my chin is approximately 90 degrees perpendicular to the flat level table. As I look to the far edge, the perimeter edge is clearly curved but it is at a 45 degree angle to my chin. A penny under my face looks round but the one across the table looks oval. So the assumption that all angles are same is provable and measurable false