With Rampage Castle System you can build a wide variety of structures. Below are some examples of the round tower tesselation
The round corner towers can be made using the E-floor/A-wall tile for the ramparts and G-floor /F-wall for the corner tower.
I’ll add some more plans on how you can make the castle below
Round Tower with Buttress
The image below shows you how to use the FC and FB floor tiles to allow room for the buttress.