To double triacontahedron
From the table of space angles we read that a space angle of the prolate rhombohedron is of the full space angle, so 20 rhombohedra form a hexecontahedron. We can then put 12 icosahedra to get a 120-hedron. Filing the niches with 20 oblate rhombohedra we get doube triacontahedron.
![[Graphics:Images/part2_gr_3.gif]](Images/part2_gr_3.gif)
From double triacontahedron to fourfolded triacontahedron
But we could put 12 triacontaherda on the hexecontahedron. Then we fill niches at points of 2-fold symmetry with 2 prolate rhombohedra and then put one prolate rhombohedron at each point of 3-fold symmetry.
At this stage we put 3 dodecahedra around each point of 3-fold symmetry and then fill niches at points of 5-fold symmetry with two layers of prolate rhombohedra.
We then put two dodecahedra at points of 2-fold symmetry, a oblate rhombohedron at each point of 3-fold symmetry and an icosahedron at each point of 5-fold symmetry.
Then we fill niches with layers of oblate rhombohedra and get a fourfold triacontahedron.