Flemish bond is one of several techniques used to bond bricks in building and construction. Each vertical row, or course, consists of stretchers—bricks laid flat with the narrow side exposed—alternating with headers—bricks laid flat with the width exposed—and the headers centered on stretchers above and below. If multiple stretchers are inserted between each header, it is considered a garden wall bond. This contrasts with the most commonly used method, running bond, which is formed entirely with stretchers. The Flemish bond is considered both a structural bond, which is used specifically to assemble a single structural unit, and a pattern bond, which may also serve as a decorative configuration on wall facings.