A post and beam structure for example, is a hierarchical structure. There is a clear sequence over several levels in which an element on one level supports an element on the next. Leverworks have no hierarchy, there is only one level. Each element supports at least one other element and is at the same time supported by at least one other element. The elements support each other mutually. In the above illustration, apart from the perifery, each element is supported by two orthers and supports two more.