The best way to understand a castle is to build one.
I'm playing with a cool set of blocks. Made by HABA, the Master Builder Set, is a good start. Unfortunately the Medieval Castle's 110 pieces with 21 shapes is still not enough. I'd need 4 or 5 sets to build anything substantial.
It's served it's purpose by giving me ideas how to proceed, so next step is I'm making my own blocks with construction lumber.
This facade of faces happened and then back to the pleasures of cardboard for model building.