I thought it might be worth creating the following image to show the difference between the flat and round earth sun motions, or rather, the apparent path and the path given by the popular, north-pole-centred-3000-mile-high-sun flat earth model.
The pink dots give the apparent position (lower) and flat earth model position (upper) for the sun at sunset on the winter solstice where I live (30° South). The yellow dots are sunset on the equinox, and the red dots sunset on the summer solstice.
The orange, green, and blue dots represent the sun's position at midday on the summer solstice, equinox, and winter solstice respectively. The dots at the top of a line represent the apparent position of the sun at these times, and the dots on the arcs represent the flat earth model position for the sun at these times.
I apologise for the lack of artistry, this was initially drawn in a 3D modelling program, and the dots added with an image editor. I wasn't really trying to make a pretty picture anyway, just something to give an idea of the relative positions of the sun at various times. Hopefully it is clear enough! Oh, and the apparent positions of the sun have been verified for my location, so no mistakes there!
Point to be debated: the difference in apparent and flat earth model locations of the sun at various times is far too great to lend any credibility to the idea of a flat earth.
Note: "Bendy light" (aka "electromagnetic acceleration") is not an acceptable explanation, as it has too many holes and has never been observed. Refraction and perspective are also unsuitable, as they do not explain the lateral or vertical difference in locations of the sun at sunset.