I found the walls of Fort Caroline different than any other fort I have visited or even drawings of forts in various books. The two large poles are pined together. The inside of the fort wall has no brace but the outside has two braces from the long pole to the fort fence. Makes for an interesting photo but I don't think it was a very effective fort. It was attacked twice and fell quickly both times.
Not easy to see but this is the outside of the wall. The braced poles and the cross piece appear to make it easier for an enemy soldier to scale the wall. At least to me who never scaled a wall! This photo was with the camera high overhead, not a great image but the only one I have that shows the outside wall.