Figure 4: Dome construction (c).
Figure 5: Bar grid.
With the above construction process various patterns can be formed, each leading to a domelike construction. In the sequel we will call the patterns that can be formed with the above rules bar grids. The bar grid of the dome of figure 4 can be drawn simplified as in figure 5. In this form the drawing looks like a tiling pattern. However, we are not interested in the tiles but in the joints between the tiles. So we have a grid consisting of straight lines representing the rods. A first investigation into the various possible bar grids soon resulted into dozens of patterns, some of which are shown in figure 6.
Figure 6: Examples of bar grids.