Fort Angle City is a laterite fortress built on the inner city wall. The four corners of the city are fortified, including the southwest corner of the city. Fort Corner, North City Fort Northeast corner city And the southeast corner city fort (Currently, the southeast corner of the fort is not visible.) The plan of every corner fort is in a diamond shape. With acute angles protruding in the moat Resembling an arrowhead The base of each fortress is made of high boards and tilted upwards. The top of the fort wall has battlements. The stairway to each fort is inside the city.