2029. The zig-zag wall (fig. 587.) is an angular wall in which the angles are all right angles, and the length of their external sides one brick or 9 in. This wall is built on a solid foundation, 1 ft. 6 in. high, and 14 in. wide. It is then commenced in zig-tag, and may be carried up to the height of 15 or 16 feet of one brick in thickness, and additional height may be given by adding 3 or 4 feet of brick on edge. The limits to the height of this wall are exactly those of a solid wall 14 in. thick; that being the width of the space traversed by the angles or zig-zag.