The behavior of a robotic agent is determined by its control program, shape and material composition, as well as external factors from its environment. Both control and morphology affect the behavior and thus must be chosen carefully to ensure robust and general behavior in various operating environments. Thus, given a set of tasks, control and morphology must be considered as one combined aspect in designing soft robots. Moreover, we can divide responsibilities into morphology and control simultaneously and synergistically to ensure robust behavior in the physical world. This joint programming of morphology and control is called co-design.