What is a redoubt, redan, and lunette?
A redoubt is an enclosed square or rectangular earthwork with four fronts and four angles. A redan is a triangular earthwork used to cover points to the rear such as bridges or river fords, and had two fronts and three angles. A lunette was employed in much the same fashion as a redan, with two faces forming a salient angle, two flanks adjoining the faces, and the rear open to interior lines.
