## How do you make a Sonobe icosahedron?

Post-It Origami Icosahedron

- Step 1: Fold Post-it in Half Glued Side Inside.
- Step 2: Fold Bottom and Top in the Center.
- Step 3: Fold Both Corners on the Upper Line.
- Step 4: Wrap It Up.
- Step 5: Fold the Corners Over.
- Step 6: Make a Square and Fold It Into Triangle.
- Step 7: Make 30 Sonobe Units.

**What is a Sonobe octahedron?**

Building a pyramid on each face of a regular octahedron, using twelve Sonobe units, results in a triakis octahedron. Building a pyramid on each face of a regular icosahedron requires 30 units, and results in a triakis icosahedron.

### How do you make a origami Sonobe?

Sonobe Unit Origami

- Step 1: Crease Center and Fold Edges to Center.
- Step 2: Fold in Half.
- Step 3: Fold Diagonals on Top and Bottom.
- Step 4: Start to Form First Interlocking Point.
- Step 5: Start to Form Second Interlocking Point.
- Step 6: Finish Forming Interlocking Point.
- Step 7: Fold Into a “W”
- Step 8: Finished Unit.

**How do you make an octahedron?**

Instructions

- Start Folding the Paper. Start with your paper white side up.
- Create Creases in the Paper. Fold the bottom right corner and align with the center crease, and then unfold.
- Align Bottom Corner with Top Edge.
- Repeat the Folds.
- Create a Mountain Fold.
- Continue to Fold the Paper.
- Finish up the Octahedron.

## How are the faces of an icosahedron stellated?

In the case of the icosahedron the faces can be extended repeatedly, and the cells form many layers, or shells, around the original icosahedron. Different combinations of these shells form different stellations, but not all possible combinations make acceptable stellations. The question is, which ones are acceptable?

**What does stellation do to a polyhedron?**

Stellation is the process of extending the faces of a polyhedron until they meet to form a new polyhedron. A number of references on stellation can be found elsewhere in this journal at the end of [3]. The new volumes of space enclosed by the extended faces are called cells.

### Is there a stellation diagram of the dodecahedron?

The facetting diagram of the regular dodecahedron and complete stellation diagram of the icosahedron are presented. Polyhedra which extend to infinity, have holes in, or have n-methoric or n-synaptic edges must be considered. Such untidy polyhedra are in contrast to the mathematically tidy ones more usually studied.

**Is the icosahedron and the dodecahedron the same thing?**

There is a beautiful and perfectly symmetrical relationship between stellations of one polyhedron and facettings of another – in this case, the regular icosahedron and dodecahedron respectively. Much of this paper explores that symmetry and the lessons to be learned from it.