TRIZ, or "theory of inventive problem solving," is a systematic approach to problem-solving that is said to be the next evolutionary step. Part of this theory includes the principle of homogeneity, which states that a homogeneous substance is made up of the same material. This principle can be applied to devices by considering what would happen if different materials were used for each part, or if all parts were made from the same material. Homogeneity can also be applied to the behaviour of parts of a system, such as making all plugs the same in an electronic system. By thinking about how homogeneity can be used in relation to a problem, it is possible to come up with more creative and innovative solutions.