Abstract: A multilateral modular structure having fastening devices for connection to similar structures, the fastening devices including the module member having surfaces terminating in edges, a tab extending outwardly from an edge of and being offset from said member, the tab being connected to the member by a hinge integral with the member and the tab, the tab having one surface extending outwardly from said edge alignable with one surface of the member, the tab having an opposite surface to its said one surface unaligned with a surface of the member, and a connecting pin adjacent said edge from which the tab extends, the pin extending and supported from said one surface of the member, said opposite surface of said tab being transversely alignable with said pin, said tab having an opening therethrough, said opening having an axis generally parallel to the axis of the pin.