Rainbow Bits Construction

George W. Hart

Rainbow Bits is a sphere of 642 CD-ROMs, over 6 feet in diameter, commissioned by Carlo Sequin for an atrium of the Computer Science building of U.C. Berkeley. I started by making a computer model, shown above. The form may be clearer in the Leonardo-style image below, which emphasizes the edges and face planes of this propello-icosahedron, consisting of sixty kites and twenty equilateral triangles. The kites are "tri-equiangular" meaning that three of their interior angles are equal.

I also made a paper model. Below, right, is the propello-icosahedron in a five-color pattern. Below, left is its dual, the propello-dodecahedron, in a six-color pattern. (I since gave both of these paper models to John Conway.)

In the sculpture, there is one CD per vertex, plus five CD's per long edge and three CDs per short edge. CDs are fairly strong but this structure wouldn't be able to support its own weight, so I designed a support structure from which it would be suspended by dozens of stainless steel support wires. I wanted to experiment with the length and positions of the wires, so I built a prototype model from surplus pink disks. With the support, it was a bit too tall to build in my studio, so I assembled it in my living room. The bottom hangs just one inch off the floor here:

I then cut the slits in the actual CDs (in my studio in New York) and shipped them to Berkeley all in a box, actually smaller than a one foot cube. At Berkeley, in a room adjacent to the atrium, I started gluing them together into sub-assemblies:

The sub-assemblies were joined into triangles which can be seen stacked in piles on the tables in the image below. Then I assembled the oak hub, fiberglass rods, stainless steel wires, and hooks which form the support structure:

The remainder of the construction had to be done in place. The next morning, I brought the components up twenty-something feet in a lift, to assemble and glue them together:

I started at the top and worked my way down to the bottom:

The total construction time on-site was about eight hours. For pictures of the final result, see my Rainbow Bits page. For other pictures of the assembly, see Prof. Carlo Sequin's U.C. Berkeley web page for this sculpture.