A simple way to come to a design for such a sphere shaped construction is the following: in the bar grid of figure 10 the midpoints of the hexagons are connected such that a pattern of triangles results (figure 11). Eight of these triangles can be used to form an octahedron (figure 12).
Figure 10: Bar grid.
Figure 11
Figure 12: Octahedron.
On this octahedron we now see a grid consisting of 24 bars and this can be used a design for the sphere of figure 13. The form of the elements has been determined such that no tension arises in the sphere. Only when closing the sphere non-rigidity of the elements is required. The relative position of the elements causes the sphere to stay in one piece: each of the elements is prevented to fall by other elements. For the sphere of figure 14, which consists of 90 elements, the icosahedron has been used as an intermediate step so that pentagons occur in the construction.
Figure 13: Sphere - 24 elements.
Figure 14: Sphere - 90 elements.