Is the problem the poor exposition? Because the answer actually is refraction. In my experience it doesn't make any difference how many references you include.

Is the problem the poor exposition? Because the answer actually is refraction. In my experience it doesn't make any difference how many references you include. They either don't read them at all, or they read them but don't address the content. So far I have been unable to get a flat earther to respond to basic information that I provide that contradicts their assertions.