## Origami stellated icosahedron!

Continuing what I started in December, I finally finished making a stellated icosahedron out of 30 Sonobe units. Each Sonobe unit corresponds to an edge of the icosahedron, and interlocks with three others to give the whole thing a remarkable degree of rigidity, even though it’s made completely out of paper.

Here are the requisite photos, showing first fivefold symmetry:

…threefold symmetry:

…and twofold:

Unlike with the cube and octahedron I made out of Sonobe units, where I just put colors together more or less randomly (only ensuring that no two touching units were the same color), with this icosahedron I very carefully researched a color scheme with some really nice mathematical properties. I’ll explain that in my next post!

Assistant Professor of Computer Science at Hendrix College. Functional programmer, mathematician, teacher, pianist, follower of Jesus.
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### 4 Responses to Origami stellated icosahedron!

1. Isaac says:

They are very beautiful, Brent, especially the five-fold.

Can I ask how long it took you to build these (not counting the time to prepare Sonobe cubes)? It looks like a great project that we can lead in a class or at a meeting.

• Brent says:

It’s a little hard to know since I made the Sonobe units in parallel with building the icosahedron, as I needed them. But actually I think the majority of time was spent making the Sonobe units. Once you have them it does not take too long to put them together. I think this would indeed make a great group project.