The dome of this chapel has twelve sections, as that of Chapel 4, but the base building is very different. Here, it is formed by six columns made of cuboctahedra, and beginning with a double hexagonal prism. The six columns and the intermediate structures joining them at the top provide twelve horizontal triangles on which the sections of the dome rest. All the cuboctahedra are of the reinforced type:

Notice that the upper cuboctahedron of each column has two rods missing, because the joining angle at the lower ball is too acute to fit another rod. The square panels and the three internal rods which support the upper triangle provide enough rigidity and strength. The following picture shows the structure which joins the columns one level under the upper triangles, where the horizontal sections of the cuboctahedra, in this orientation, are regular hexagons:

The sections of the dome are segments of circular tetrahedric curves made of 27 tetrahedra. These segments join one another forming a regular dodecagon, as shown in the following picture. The spire of the dome is built on this dodecagon:

As the join of the sections at the top is quite weak, it becomes necessary to keep the double blue rods which hold them together, as shown above in the first pictures of this page. However, no other scaffolding is required to build this dome.