I've been watching the bbc's Secrets of the Castle series and seeing the castle being built reminded me of something that kinda bugs me. It seems like so many of the medieval castles don't have all of their walls coming together at 90 degree angles. Is there a reason for this? Is having nice and consistent angles just a modern sensibility?
edit: i guess i should clarify that i'm asking about the outer walls of the castle's yard specifically (most of the rooms seem to be regular)
If it was built after cannons were in regular use, angled walls provide better defense since a cannonball will glance off rather than hit perpendicularly/with full force.
I'm not an expert; but I think the main reason was to use the land most efficiently. The topography would usually make it harder to use basic geometric shapes while there is practically no reason for using those shapes since they did npt require furnitures.