Tetrated dodecahedron

The tetrated dodecahedron is a near-miss Johnson solid. It was first discovered in 2002 by Alex Doskey. It was then independently rediscovered in 2003 and named by Robert Austin.[1]

Tetrated dodecahedron
Typenear-miss Johnson solid
Faces4+12 triangles
12 pentagons
Edges54
Vertices28
Vertex configuration4 (5.5.5)
12 (3.5.3.5)
12 (3.3.5.5)
Symmetry groupTd
Propertiesconvex

It has 28 faces: twelve regular pentagons arranged in four panels of three pentagons each, four equilateral triangles (shown in blue), and six pairs of isosceles triangles (shown in yellow). All edges of the tetrated dodecahedron have the same length, except for the shared bases of these isosceles triangles, which are approximately 1.07 times as long as the other edges. This polyhedron has tetrahedral symmetry.

Topologically, as a near-miss Johnson solid, the four triangles corresponding to the face planes of a tetrahedron are always equilateral, while the pentagons and the other triangles only have reflection symmetry.

Net

The 12 pentagons and 16 triangles are colored in this net by their locations within the tetrahedral symmetry.

Dodecahedron
(Platonic solid)
Icosidodecahedron
(Archimedean solid)
Pentagonal
orthobirotunda

(Johnson solid)
gollark: Oh, and their wordlist is bad and contains various easily confusable words.
gollark: ~~I believe their official thing also needs an internet connection to work, even though it could simply not do so.~~ It does not, actually.
gollark: To spite them, I have an open source reimplementation of the algorithm somewhere in my archive folder.
gollark: And then shut down any independent research or reimplementations of it!
gollark: They somehow managed to make money off a really simple mapping of coordinates to words!

See also

Notes

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