This paper (cardstock) model of a Norman castle is designed after the general Norman style of castles, where all the towers are square. The keep has four square towers and is suggestive of the keeps at Dover Castle and the Tower of London. Round towers were introduced into castle construction at a later period (around 1100). The use of square towers makes this castle model relatively easy to build. Simply print off the pages onto cardstock (I prefer 110 lb), cut them out and glue them together.