OK, so if pictures aren't allowed to be used, then how about video?
It may not be the best example, but it does show a ROUND earth.
Also, if the planet was flat, then there would only be one time in which the sun can be seen, and one for night time. What I mean is, the sun would only be visible from 1 AM to 12 PM, due to the fact that the planet were flat. There would be no dusk. From at 12 PM and 12 AM you would also be able to see the sun and the moon at the same time, in plain sight.
Here's another video:
Aristotle once said:
"There are stars seen in Egypt and [...] Cyprus which are not seen in the northerly regions."
This would only be possible if the Earth were round.
Finally, Aristotle also said that the shadow of Earth on the moon during a lunar eclipse is round.
Your move, Tom.