Torsion springs is a complex design principle in all spring categories,and the types vary widely,so the theory involved in design is also the most complicated. The ends of the springs are secured to other components that pull them back to their original position as the other components rotate about the center of the spring,creating a torque or rotational force. The spring can store and release energy. The direction of the wind is also important for the application of it, since the bearing/attachment position of the leg must be on the left or right side during assembly.