I saw yesterday night a wonderful documentary about the Castle of Chambord on Arte channel. At some point, an old map of the castle was shown and it triggered immediately my interest because the dungeons are not centered on the corners of the castle. I wondered why, and more importantly how. I am not sure to completely buy the current explanation where the castle was designed on a grid because it does not explain the perfect ratio between the dungeons' diameter and the size of the main body of the castle. And then I saw something simple, really simple, that could explain how the plan of castle was designed. Here's my little experiment.