Fort Sanders was never completed, hence it had no east wall (lower one above) and most of the south wall (left one) was also unfinished at the time of the battle.

But I liked this public domain 1863 sketch of what the complete fort might have looked like, attributed by the Library of Congress to Union soldier John G. Orth, and so I used it for the cover of my novel.

Notice how Orth drew a big American flag rising from the center of the compound (probably part of his overall idealization) but also sketched in the (more or less) accurate location of the American flag on the left side of the northwest bastion.