## A ZOMETOOL MODEL OF A 16 CELL

Here we describe how to build an edge-first projection of the 16 cell, one of the six regular polytopes in 4-dimensional space, using the zometool system. For the model you need

- 6 balls,
- 5 long blue (b2) struts,
- 8 long yellow (y2) struts.

Of course one can scale down the model to b1-y1 (medium size) or to b0-y0 (mini version).

For further information and instructions you might also wish to consult one of the following webpages:

- Eusebeia 4d visualization,
- David Richter's webpage, where I saw the model first.

The pictures below were taken by Eva-Maria Gassner.

**Step 3**

Add a blue strut emanating from the tip of the yellow pyramid that points to the other side of the square. This is the central edge of the projection.

This Zometool model of the 16 cell shows an edge at the centre of the projection, which is surrounded by 4 tetrahedral cells. In 4d these are regular tetrahedra, but they appear squashed because of the projection. Each of these cells has