The Fin-Ray effect®, invented in 1997 by Leif Kniese and patented by EvoLogics GmbH Berlin describes a flexible construction to transfer forces. The structure is inspired by rays of fishes and is surprisingly simple. Fishes have a basic structure consisting of two bones that are attached by elastic connective tissue. The tail fin is the prime mover for movement. It consists of several basic structures stacked one above the other. It is very important that the structure is light but strong enough, because excess weight is inappropriate in terms of energy losses. The design simulating a fish fin consists of two longitudinal fibers, which are on either side (top) attached. Among the longitudinal fibers are cross fibers that keep the whole structure after assembly. The longitudinal and cross fibers are connected with flexible links that allow movement between them. source