I managed to silence, so far, 4 different flat earthers. They are maniacs even more crazy than leftists. Their main shtick is that the horizon is flat, therefore the earth is flat. The solution to this is anti-intuitive and few can realise it. The horizon is a circle that goes around you so it looks flat, just like a coin or a hula hoop looks flat edge-on. Simple. The other curve is from you to the horizon so likewise you cannot perceive it, it is a coin held vertically edge on. This destroys their main shtick and they do not have much else, but what they do have is also (obv) flawed by not having the correct frame of reference. It's enjoyable to debate them, except for the abuse you get. Yes, it is classic well-poisoning. I knew a bloke who wrote a book about truth (recently awakened) and he had also fallen for flat-earth, this makes my heart bleed because his family are disowning him, focussing on the flat earth bit. That is what it is for - to ruin peoples credibility with people they know. Insidious stuff.