I can't tell if you really are that stupid, or you're just pretending to be that stupid.
With your eyes you can see a ship disappear into the horizon from 6 miles away.
WIth a 8x optical zoom you can see a ship disappear into the horizon many miles beyond the first test.
With a 16x optical zoom you can see a ship disappear into the horizon many miles beyond the second test.
With a 32x optical zoom you can see a ship disappear into the horizon many miles beyond the third test.
You can continue using more and more powerful telescopes to see these ships disappearing into the horizon up to 250 miles away with the strongest of the commercial telescopes.
So tell me exactly where the Earth starts to curve?