A fortress is only as strong as the angles it can deny. First, close the main gates and put a sally port— that’s the choke point you can keep a single guard on. Then cover the corners with bastions; give each one a clear line of fire to the next. Don’t forget the ditch—water or mud makes a bad first line of defense, and mud makes your enemies slip. Keep a second wall out back, spaced far enough that if the outer line falls, the inner one is still holding. And always have a fallback trench, because no plan stays perfect when the enemy is drunk on your mistakes.