I ran into this on Facebook, where I posted it in 2011. That was the year before I started this blog.

# An Intermediate Form Between the Icosidodecahedron and the Rhombic Triacontahedron

This polyhedron combines the faces of an icosidodecahedron (red and blue) with the those of a rhombic triacontahedron (green). The gaps between those two sets of polygons are the yellow rectangles. I made this using the “morph duals by expansion” function of *Stella 4d*: *Polyhedron Navigator.* You can try this program for yourself, free of charge, at http://www.software3d.com/Stella.php.

# Blues and Violets

This was created using *Geometer’s Sketchpad* and *MS-Paint.*

# At 53, My Age Is a Prime Number Again

It has long been a tradition of mine to make star polygons to mark my birthdays. Since I’m 53 today, here’s a 53-pointed star.

# A Tessellation for the New Year MMXXI

Here’s another version, with different colors:

# A Tessellation of Regular Hexagons and Squares, as Well as Equilateral and Elongated Hexagons

Here’s the same tessellation, using different colors:

# A Tessellation Featuring Regular Enneagons and Triangles, as Well as Equilateral Three-Pointed Stars

Here’s a second version, with different colors:

# A Tessellation Featuring Regular Octagons and Triangles, Together with Equilateral Four- and Six-Pointed Stars

This tessellation started with a single equilateral triangle, surrounded by regular octagons. The one shown below is the same tessellation, but with different colors.

# A Tessellation Featuring Regular Heptagons and Triangles, Together with Equilateral Four- and Six-Pointed Stars

This started with the idea of attaching a regular heptagon to each side of an equilateral triangle. From there, it took on a life of its own.

Here’s another version, with different colors:

# A Dodecahedron, with Mandalas

The mandala used here first appeared in this blog-post. I then used *Stella 4d: Polyhedron Navigator* to put those images on the faces of a dodecahedron. If you’d like to try this program yourself, you can do so, for free, at http://www.software3d.com/Stella.php.