Tetrahelices - two bead models of Boerdijk–Coxeter helix

There is a helical tower based on the Boerdijk–Coxeter helix in Mito-shi, Ibaraki-ken, Japan:

Art Tower MIT

So, during my visit to Nagoya this May, I made several tetrahelices as souvenirs for my friends there. Since I brought many tubular beads with different colors to choose from, so I decided to use different color for three helical edges in each tetrahelix. In total, there should be four possible arrangements or two enantiomer pairs. But I only made two of them shown in the following picture. After I made these two tetrahelices, so many people also like to have this model, so I made two more tetrahelices before I left Japan.