Strike-slip duplexes are passive structures; they form as a response to displacement of the bounding fault rather than by the stresses from plate motion. Each horse has a length that varies from half to twice the spacing between the bounding fault planes. Depending on the properties of the rocks and the fault, the duplexes will have different length ratios and will develop on either major or subtle offsets, although it is possible to observe duplex structures that develop on nearly straight fault segments. Because the motion of the duplexes may be heterogeneous, the individual horses can experience a rotation with a horizontal axis, which results in the formation of scissor faults. Scissor faults exhibit normal motion at one end of the horse and a thrust motion at the other end. Because strike-slip duplexes structures have more horizontal motion than vertical motion, they are best observed on a map rather than a vertical projection and are a good indication that the main fault has a strike-slip motion.