About RobertLovesPi

I go by RobertLovesPi on-line, and am interested in many things, a large portion of which are geometrical. Welcome to my little slice of the Internet. The viewpoints and opinions expressed on this website are my own. They should not be confused with those of my employer, nor any other organization, nor institution, of any kind.

The Pentagonal Hexacontahedron, and Related Polyhedra

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The Pentagonal Hexacontahedron

As the dual of the snub dodecahedron, which is chiral, this member of the Catalan Solids is also chiral — in other words, it exists in left- and right-handed versions, known an entantiomers. They are mirror-images of each other, like left and right gloves or shoes. Here’s the other one, by comparison:

Penta Hexeconta enantiomer

It is always possible to make a compound, for a chiral polyhedron, from its two enantiomers. Here’s the one made from the two mirror-image pentagonal hexacontahedra shown above:

Compound of enantiomorphic pair

Stellating this enantiomorphic-pair-compound twenty-one times produces this interesting result:

stellating

And, returning to the unstellated enantiamorphic-pair-compound, here is its convex hull:

Convex hull

This convex hull strikes me as an interesting polyhedron in its own right, so I tried stellating it several times, just to see what would happen. Here’s one result, after seventeen stellations:

Stellation17

Software credit:  I made these rotating images using Stella 4d:  Polyhedron Navigator. That program may be bought at http://www.software3d.com/Stella.php, and has a free “try it before you buy it” trial download available at that site, as well. I also used Geometer’s Sketchpad and MS-Paint to produce the flat purple-and-black image found on faces near the top of this post (and, by itself, in the previous post on this blog), but I know of nowhere to get free trial downloads of these latter two programs.

Decorated Icosahedron

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Decorated Icosahedron

The image on the faces appears in the last post here, and was made using Geometer’s Sketchpad and MS-Paint. Putting this image on the faces of an icosahedron, and then creating this rotating .gif file, was accomplished using another program, Stella 4d, which you may try for free at http://www.software3d.com/stella.php.

Turquoise and Onyx

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Turquoise and Onyx

Three separate programs were used to make this: Geometer’s Sketchpad, MS-Paint, and Stella 4d. The latter program was written by a friend of mine, and may be bought (or tried for free) here: www.software3d.com/stella.php.

Each of the turquoise images contains 32 circles, and each is on a face of a single rotating rhombic dodecahedron. That polyhedron, though, is obscured by having black faces against a black background, with edges and vertices not shown. You can see no more than one of an entire rhombic face at a time, and that happens only when the “lighting” provided by Stella 4d makes it appear slightly illuminated.

The Thirty All-Seeing Eyes of the RhombicTriacontahedron

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The Thirty All-Seeing Eyes of the RhombicTriacontahedron

Software used: