# Monthly Archives: February 2022

## A Tessellation Featuring Regular Tetraicosagons, Equiangular Octagons, Isosceles Trapezoids, and Isosceles Triangles

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## A Fourth Tessellation Featuring Crescents

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## A Tessellation Featuring Elongated Dodecagons and Other Polygons

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## A Tessellation Featuring Regular Octadecagons, Equilateral Triangles, and Isosceles Triangles

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## Tessellation Featuring Regular Hexagons and {9,4} Enneagrams, as Well as Other Polygons

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# A Symmetrohedron Derived from the Rhombic Dodecahedron

To make this symmetrohedron, I augmented the faces of a rhombic dodecahedron with prisms, then formed the convex hull of the result. All faces except for the red rhombi are regular. This was made using *Stella 4d*, which you can try for free here.

# A Polyhedron with 36 Faces

Of the 36 faces of this polyhedron, 12 are rhombi, while the other 24 are irregular hexagons. I made it using *Stella 4d*, which you can try for free right here.

# Modified Rhombicosidodecahedra, as Building Blocks for Larger Structures

In the two posts right before this one, I’ve been exploring simple structures made of modified rhombicosidodecahedra, and today I’m going to post a much larger, more complex one. Here’s the rhombicosidodecahedron — the original Archimedean solid which started all of this:

The modified forms of this polyhedron which I’m using as building-blocks are all among the 92 Johnson solids. Here are the two which have already appeared in the last two posts on this blog: the diminished rhombicosidodecahedron (J76) and the parabidiminished rhombicosidodecahedron (J80).

For this new, more ambitious construction, I’m going to need some more pieces, starting with the metabidiminished rhombicosidodecahedron (J81), which will be useful to make angles.

The Johnson solid called the tridiminished rhombicosidodecahedron (J83) can be used to make three-valent vertices.

Finally, here’s the more complex structure for which I needed all these pieces. It could be extended outwards indefinitely, in a manner similar to the tessellation of the plane with regular hexagons.

To make these polyhedral images, I use a program called *Stella 4d*. If you’d like to give it a try, for free, please visit this website.

# The Triple Rhombicosidodecahedron

This is the rhombicosidodecahedron, one of the thirteen Archimedean solids.

Several of the 92 Johnson solids are modified forms of this polyhedron, such as J76, the diminished rhombicosidodecahedron (shown below). It is formed by removal of a pentagonal cupola from a rhombicosidodecahedron, exposing a decagonal face.

Another variant of this Archimedean solid may be created by removing two pentagonal cupolas, exposing decagons on opposite sides of the figure. This solid, J80, is called the parabidiminished rhombicosidodecahedron.

Two J76s and one J80 can then be joined together, at their decagonal faces, to form this: the triple rhombicosidodecahedron.

I made these using *Stella 4d*, a program you can try for free at this website.