Abstract: A manually operable mechanical puzzle including four members, each having separable first and second end body portions. Each body portion has an end connector attached to an outer end for pivotal attachment to one of the other members to form a continuous loop comprised of the four members. The first and second body portions of a member are separably attached together at an inner end for partial rotation about an inner end joint. Each of the body portions has a pair of generally oppositely facing attachment faces, each with a square element rotatably attached thereto by a face joint for partial rotation thereabout. When two of said members are pivoted into position laterally adjacent to each other, the first body portions are rotatable as a unit about a common axis formed by the partial inner end joints to selectively interchange attachments of the body portions.