a flat earth was considered something of a joke, even in pythagora's time. it did become something of an official policy in midevil times, for reasons that were entirely political. even when it was official cannon, only a minority actually believed. pretty much the same fringe that insist on it today. it is kind of a joke that you can find anecdotal evidence for almost anything. which doesn't mean anecdotal claims are always wrong, the fact that it can, has earned it a less then favorable reputation. most jokes don't age that well, and a flat earth is a very old joke indeed. only disc world had 'turtles all the way down". yes my eyes do not lie, the hull of a ship, sailing away from shore, does not remain visible for as long as the tip of its mast. also i grew up in a forest on the side of a mountain, and that earth was very definitely not flat either.