The cool thing about using a tessellation as a base is that it basically gives you a small square in the middle of your main square. The number, size and position of the small square can be manipulated, so it is very flexible. The first is the Grand Castle. It features a large central tower surrounded by a wall with four smaller towers at the corners. Once I started folding it I realized that I would also have a tower in the center of each edge wall, resulting in a total of nine towers. A second version, called the Armory is a single block of a building with four towers in the corners and no central tower. The third, the Castle Keep, consists of six towers in two groups. In the front is a gatehouse flanked by two small guard. In the back is a a large tower with a hall on each side. In between is a central courtyard. I'm thinking I can combine the castle technology with some ideas from the Origami from Space series to create all kinds of domes and spires, and virtually any kind of architectural structure. .