I'd like to see a reply to this. As far as I can see, there are three issues that need resolving:
1) If the sun is round and the earth is flat, and the sun casts a round "spotlight" on the earth, why does everyone in the world get 12 hours of daylight at an equinox? Shouldn't those at the equator get a lot more than that? Shouldn't those in, say, Canada, get a lot less?
2) If the time zones' divisions are relatively flat because the sun's light is cast in an oval shape, how is this oval distortion accomplished? If not, why are the time zones' divisions relatively flat?
3) If the sun's light is cast in a round/oval shape, why isn't the southern hemisphere much colder in their summer than the northern hemisphere is in theirs (same amount of light for same amount of time over a larger surface)?