When you reach the end of the flat plane....so you wrap around the edge and continue upside down?

That is the strawman argument. You believe in an endless universe, yet a plain has to have an edge? That shore you step on is the antarctica that surrounds our pond. What lies beyond that, we are not allowed to find out. Google the antarctic treaty, during the 1950's all countries of the world agreed on 1 thing, independent exploration of anything below 60 degrees is not allowed. Yes you can go to visit by paying 30k to a tour company, they show u penguins and some fake pole in the snow, and call it south pole. But thats about it. If you wanted to make an independent expedition, just the fees to apply for a permit would cost you over 200k, and they will decline the application and keep the non refundable fees. And nobody is allowed to even question this treaty until it runs out in 2043...