On December 14, 2019, we hosted the Bay Area Arts & Math (“BAAM!”) group at our house. As part of the fun, we did a group construction of the vertex-first projection of the 120-cell using Zometool and my own 3d-printed custom struts.

in progress

We didn’t get it finished in time, since the custom struts often have a loose fit. They are my own design, created using vZome and printed at Shapeways. Jacob Rus suggested a nice innovation, using strips of parchment paper wherever we had a loose-fitting strut. I completed the build the next day.

threefold

pentagons

twofold

I had owned the custom struts (olive, maroon, and lavender) for almost ten years. I first printed them in 2010, and in October of that year my son and I created the (first ever?) physical realization of the vertex-first projection.

threefold original

twofold original

We didn’t have much space in that house, so it just stayed on the coffee table for a while, finding use as a backdrop for photos:

as a backdrop

The revived instantiation is now permanently installed in our family room.