Brawny 3-ply twongs

An important trade-off in the design of twongs is the length of the overlapped, or 2-ply section. If the 2-ply section is short, the junction is not strong. If it is long (it can be extended to up to 50% of the inter-vertex distance) it creates a concentration of bending stress that prevents the composite member from bending smoothly. The maximum overlap is limited to 50% of the inter-vertex distance because the overlaps from each vertex cannot overrun each other if the construction is to remain 2-ply.

Going to a 3-ply construction, i.e., where the twongs are formed by twisting a triple strand of wire, opens new possibilities.

In a 3-ply construction the overlaps can now be 100% of the inter-vertex distance. That means the inter-vertex distance can be cut in half for the same length of overlap, permitting much brawnier and stronger structures to be built. The structure at the vertex is still single-ply as before, but the overlapping of the overlaps makes for a 3-ply composite structure between vertices.