Border Tower 21

This started life as a line drawing ages ago. I was going through a bunch of old things and decided this was something I wanted to finish. It's part of a line of defences along a river in my main fictional world. They use flags to communicate to neighbouring towers. And there are two forts to the rear. Small settlements have cropped up around a couple of the towers, wither hunters and other peddlers trading with the local garrisons.