A spring is formed of a relatively thin sheet of spring material, which is constricted and held in place at each end forming a bell curve being located between two substantially planar members. As additional compressive force is applied in the vertical direction, the curve then compresses and starts to form sine waves. In an improved embodiment of the present invention, the sine wave spring is formed in a wedge shape, so that it is gradually taller and more progressive. This embodiment has been tested for use as a trailer spring with positive results. This wedge-shaped sine wave spring provides even more advantages over the Prior Art. The wedge-shaped prototype illustrates also how the present invention may be expanded to other shapes, in order to alter the spring characteristics, and also for packaging and other concerns.