It cannot be properly sketched on a 2d paper, because it is a 3d phenomenon, both above and over Earth, that takes place during sunsets and sunrises.
If Earth was a ball, with the blackness of 'space' above it, the Sun would curve downward, at sunset, and would NOT light up the sky above us, it would curve down, and the sky would be black above us, not what happens, and it also proves that the Earth IS flat...
How could the Sun not be seen, past a horizon, yet light up the skies above us, if it is simply 'black space', above the Earth?