Instead of beginning with the enclosed tetrahedra, I concentrated on the outer edges of the tetrahelix to make them the most visible part of the structure. I made a small model with twist-ties, thin wire, and stiff straws, then outlined the struts of each “face” between the outer curved backbones with different colors of yarn. When I undid twist-ties holding one “face” and the model fell open.
An efficient method of stringing the sections of a tetrahelix became very clear!
Thirteen struts per face, thirty-nine total, and three spines make a helix with a twist of almost 180°.
Water supply line became the spines. Seven pairs of holes drilled equidistant from each other provide anchor points for the ribs.
I strung three sets of 13 ribs like beads on lengths of wire. Then I fastened them zig-zag fashion by threading a short length of wire through one hole, catching the long wire between each rib, then back through the second hole. Pushing the ends of the fastener-wire in and out of each pair of holes makes the joint secure.