Ninth Stellation of the Icosahedron

 

ninth stellation of the icosahedron

This model is made of 12 pentagonal pyramids and uses 5 different colors. Each pyramid will contain one of each of the 5 colors. You will need to use the template below to make 12 pieces of each color.

To see the full-sized template click on this image:       9th stellation of icosahedron template

In his book, Polyhedron Models, Father Wenninger gives this description of the pyramids that you must make;

(1) Y B O R G

(2) B Y R O G

(3) O B G R Y

(4) R O Y G B

(5) G R B Y O

(6) Y G O B R

Create a pyramid with the colors of (1) ... Y B O R G.

You must be consistent in how you order the colors in your pyramid! All of your pyramid faces in this first half of the polyhedron must be arranged in the same clockwise or counter-clockwise direction as you glue them together.

I have arranged my 5 faces in a counter-clockwise manner as they were viewed from the top of the pyramid. It will be necessary to severely trim the tabs of your pyramids near their peaks in order to not have bunched material interfering with your star's point.

On the right-hand tab of the first face (in this first case, the yellow face) mark the number of this pyramid ... in this case # 1.

Create your first 6 pyramids in this manner. Glue the faces together in a counter-clockwise arrangement and number each finished pyramid on the right tab of the first color.

Now arrange pyramids #2 through #6 in a counter-clockwise manner (according to their numbers) around pyramid #1. You will be gluing the left-hand tab of the first face in pyramid #2 to the numbered tab of pyramid #1. Then you will glue the left-hand tab of the first face of pyramid #3 to the right-hand tab of the second face in pyramid # 1. Continue in this manner ... left-hand tab of pyramid #4's first face to the right-hand tab of next face in pyramid #1.

You should now start to see part of the 3-pointed stars that will share the same facial plane and have the same color.

9th stellation of icosahedrion

The last 6 pyramids of this polyhedron use the same color arrangement as the first 6 pyramids that are listed above ... but they should be assembled in a clockwise manner. You should number them, as you did the first 6 pyramids, on the right-hand tab of the first face in the list. However, this time number them 1R, 2R, etcetera to remind yourself that these are arranged in the reverse order. To continue your polyhedron, you will attach pyramid 6R next. Then you will attach 5R, 4R, etcetera.

If the placement of a piece is not apparent, reexamine your pyramids for consistent direction of assembly. This is a common error.

As your polyhedron becomes more complete, you should be able to discern the same-colored 3-pointed stars. As you turn your polyhedron, new same-colored, 3-pointed stars will become visible.

The last piece of this assembly is difficult because there are 12 pairs of tabs to be glued and you can't hold them from the inside of the polyhedron or clamp them. Plan for this gluing to take a long time. Glue one or two pairs of tabs at a time and then exert pressure on the whole polyhedron to hold the tabs in place until they have had time to dry.