Adding a round spiral tower to your boxy base is fairly simple and is a great way to add a route between floors. Not to mention, it looks badass! I created this guide for builders that need a little help getting started.



First, start with the round foundation that wrap one of your corners similar to this:

http://steamcommunity.com/sharedfiles/filedetails/?id=779614989



Since we're attaching a round tower to a square structure, just square off the inside corner. This will allow you to add doors and windows (I prefer one-way from the room looking into the stairwell):

http://steamcommunity.com/sharedfiles/filedetails/?id=779615067





You can end the tower at the roof of the structure, where you can use the overhang battlement pieces along with the straight battlement pieces like this:

http://steamcommunity.com/sharedfiles/filedetails/?id=779615079




Or, you can continue building the tower up above your roof, which you can switch to all round walls since you no longer need to square off the inner corner.

http://steamcommunity.com/sharedfiles/filedetails/?id=779615096

It can eventually look something like this:

http://steamcommunity.com/sharedfiles/filedetails/?id=779614981



You also have the option of adding a free standing tower, that is not part of your structures:

http://steamcommunity.com/sharedfiles/filedetails/?id=779614950

You will notice that I have a squared off, 1 wall hieght, corner at the base of the tower so I could add a double door and window for added security and a little more space for a bed and some storage.




For added security, you can add doors and windows to every floor, which will break up the spiral stairwell route into secure sections.

http://steamcommunity.com/sharedfiles/filedetails/?id=779615198