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.

A few photos from workshop in the Nagoya City University

During my visit to Japan this May, Prof. Sonoda and Horibe kindly arranged a special workshop in the Nagoya City University on May 10, 2014. Here are a few photos from the workshop which connecting the Sangaku problems and mathematica beading.

In addition to this workshop, Horibe and I will also give a similar workshop in the Bridges meeting (Seoul) this year.