Very nice and simple explanation! That drawing is so cute, but if it were accurate, either the Earth would be so small that we could travel around the World by foot in 30 minutes, or that building and that person are a "few" kilometers tall! :-)
By the way, the Flat Earth Theory is being promoted by DAARPA, as part of their Narrative Networks Study.
They are investigating what leads some people into believing one theory over another... and what happens inside people's brains when confronted with facts that either support or refute their interpretation of the World!. ;-)