Abstract: An improved joint for connecting the ends of tubes for the purpose of assembling a geodesic dome or truss structure (FIG. 6). The tube ends form top and bottom hooks (A4) which face away from each other. The hooked ends (A4) facilitate the attachment of adjacent tubes to the unifying joint by gripping a common top and bottom washer (3). The inner washers (3) are used as tension rings for restricting the movement of the tubes by which they are hooked. The structure is stiffened when the hooks are pressed down into a flattened position by the outer top and bottom washers (2). The outer top and bottom washers are sandwiched by a single nut and bolt assembly (1,5). As the nut and bolt assembly (1,5) is tightened pressure is applied to the outer washers which press the booked ends (4A) of the tubes backwards into a flattened position. The initial condition of the joint is loose to allow adjustments of the positioning of the tubes within the structure.