Compound of dodecahedron and icosahedron

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First stellation of icosidodecahedron
Compound of dodecahedron and icosahedron.png
Type Dual compound
Coxeter diagram CDel nodes 10ru.pngCDel split2-53.pngCDel node.pngCDel nodes 01rd.pngCDel split2-53.pngCDel node.png
Stellation core icosidodecahedron
Convex hull Rhombic triacontahedron
IndexW47
Polyhedra1 icosahedron
1 dodecahedron
Faces20 triangles
12 pentagons
Edges60
Vertices32
Symmetry group icosahedral (Ih)

In geometry, this polyhedron can be seen as either a polyhedral stellation or a compound.

Contents

As a compound

It can be seen as the compound of an icosahedron and dodecahedron. It is one of four compounds constructed from a Platonic solid or Kepler-Poinsot solid, and its dual.

It has icosahedral symmetry (Ih) and the same vertex arrangement as a rhombic triacontahedron.

This can be seen as the three-dimensional equivalent of the compound of two pentagons ({10/2} "decagram"); this series continues into the fourth dimension as the compound of 120-cell and 600-cell and into higher dimensions as compounds of hyperbolic tilings.

Polyhedron 12.png
Polyhedron 20.png
A dodecahedron and its dual icosahedron
Polyhedron 12-20 blue.png
Polyhedron 12-20 dual blue.png
The intersection of both solids is the icosidodecahedron, and their convex hull is the rhombic triacontahedron.
Polyhedron pair 12-20 from blue.png
Polyhedron pair 12-20 from yellow.png
Polyhedron pair 12-20 from red.png
Seen from 2-fold, 3-fold and 5-fold symmetry axes
The decagon on the right is the Petrie polygon of both solids.
Polyhedron pair 12-20 big.png
Polyhedron small rhombi 12-20 dual max.png
If the edge crossings were vertices, the mapping on a sphere would be the same as that of a deltoidal hexecontahedron.

As a stellation

This polyhedron is the first stellation of the icosidodecahedron, and given as Wenninger model index 47.

The stellation facets for construction are:

First stellation of icosidodecahedron facets.png First stellation of icosidodecahedron pentfacets.png First stellation of icosidodecahedron.png

In the film Tron (1982), the character Bit took this shape when not speaking.

In the cartoon series Steven Universe (2013-2019), Steven's shield bubble, briefly used in the episode Change Your Mind, had this shape.

See also

Related Research Articles

In geometry, a dodecahedron or duodecahedron is any polyhedron with twelve flat faces. The most familiar dodecahedron is the regular dodecahedron with regular pentagons as faces, which is a Platonic solid. There are also three regular star dodecahedra, which are constructed as stellations of the convex form. All of these have icosahedral symmetry, order 120.

<span class="mw-page-title-main">Kepler–Poinsot polyhedron</span> Any of 4 regular star polyhedra

In geometry, a Kepler–Poinsot polyhedron is any of four regular star polyhedra.

In geometry, a polyhedral compound is a figure that is composed of several polyhedra sharing a common centre. They are the three-dimensional analogs of polygonal compounds such as the hexagram.

<span class="mw-page-title-main">Stellation</span> Extending the elements of a polytope to form a new figure

In geometry, stellation is the process of extending a polygon in two dimensions, polyhedron in three dimensions, or, in general, a polytope in n dimensions to form a new figure. Starting with an original figure, the process extends specific elements such as its edges or face planes, usually in a symmetrical way, until they meet each other again to form the closed boundary of a new figure. The new figure is a stellation of the original. The word stellation comes from the Latin stellātus, "starred", which in turn comes from Latin stella, "star". Stellation is the reciprocal or dual process to faceting.

<span class="mw-page-title-main">Great dodecahedron</span> Kepler-Poinsot polyhedron

In geometry, the great dodecahedron is a Kepler–Poinsot polyhedron, with Schläfli symbol {5,5/2} and Coxeter–Dynkin diagram of . It is one of four nonconvex regular polyhedra. It is composed of 12 pentagonal faces, intersecting each other making a pentagrammic path, with five pentagons meeting at each vertex.

<span class="mw-page-title-main">Final stellation of the icosahedron</span> Outermost stellation of the icosahedron

In geometry, the complete or final stellation of the icosahedron is the outermost stellation of the icosahedron, and is "complete" and "final" because it includes all of the cells in the icosahedron's stellation diagram. That is, every three intersecting face planes of the icosahedral core intersect either on a vertex of this polyhedron, or inside of it.

<span class="mw-page-title-main">Small stellated dodecahedron</span> A Kepler-Poinsot polyhedron

In geometry, the small stellated dodecahedron is a Kepler-Poinsot polyhedron, named by Arthur Cayley, and with Schläfli symbol {52,5}. It is one of four nonconvex regular polyhedra. It is composed of 12 pentagrammic faces, with five pentagrams meeting at each vertex.

<span class="mw-page-title-main">Great stellated dodecahedron</span> Kepler–Poinsot polyhedron

In geometry, the great stellated dodecahedron is a Kepler-Poinsot polyhedron, with Schläfli symbol {52,3}. It is one of four nonconvex regular polyhedra.

<span class="mw-page-title-main">Great icosahedron</span> Kepler-Poinsot polyhedron with 20 faces

In geometry, the great icosahedron is one of four Kepler–Poinsot polyhedra, with Schläfli symbol {3,52} and Coxeter-Dynkin diagram of . It is composed of 20 intersecting triangular faces, having five triangles meeting at each vertex in a pentagrammic sequence.

<span class="mw-page-title-main">Compound of five tetrahedra</span> Compound polyhedron

The compound of five tetrahedra is one of the five regular polyhedral compounds. This compound polyhedron is also a stellation of the regular icosahedron. It was first described by Edmund Hess in 1876.

<span class="mw-page-title-main">Compound of ten tetrahedra</span> Polyhedral compound

The compound of ten tetrahedra is one of the five regular polyhedral compounds. This polyhedron can be seen as either a stellation of the icosahedron or a compound. This compound was first described by Edmund Hess in 1876.

<span class="mw-page-title-main">Compound of cube and octahedron</span> Polyhedral compound

The compound of cube and octahedron is a polyhedron which can be seen as either a polyhedral stellation or a compound.

<span class="mw-page-title-main">Compound of great icosahedron and great stellated dodecahedron</span>

There are two different compounds of great icosahedron and great stellated dodecahedron: one is a dual compound and a stellation of the great icosidodecahedron, the other is a stellation of the icosidodecahedron.

<span class="mw-page-title-main">Great grand stellated 120-cell</span> Regular Schläfli-Hess 4-polytope with 600 vertices

In geometry, the great grand stellated 120-cell or great grand stellated polydodecahedron is a regular star 4-polytope with Schläfli symbol {5/2,3,3}, one of 10 regular Schläfli-Hess 4-polytopes. It is unique among the 10 for having 600 vertices, and has the same vertex arrangement as the regular convex 120-cell.

<span class="mw-page-title-main">Faceting</span>

In geometry, faceting is the process of removing parts of a polygon, polyhedron or polytope, without creating any new vertices.

<span class="mw-page-title-main">Stellation diagram</span>

In geometry, a stellation diagram or stellation pattern is a two-dimensional diagram in the plane of some face of a polyhedron, showing lines where other face planes intersect with this one. The lines cause 2D space to be divided up into regions. Regions not intersected by any further lines are called elementary regions. Usually unbounded regions are excluded from the diagram, along with any portions of the lines extending to infinity. Each elementary region represents a top face of one cell, and a bottom face of another.

<span class="mw-page-title-main">Medial rhombic triacontahedron</span> Polyhedron with 30 faces

In geometry, the medial rhombic triacontahedron is a nonconvex isohedral polyhedron. It is a stellation of the rhombic triacontahedron, and can also be called small stellated triacontahedron. Its dual is the dodecadodecahedron.

<span class="mw-page-title-main">Great rhombic triacontahedron</span> Polyhedron with 30 faces

In geometry, the great rhombic triacontahedron is a nonconvex isohedral, isotoxal polyhedron. It is the dual of the great icosidodecahedron (U54). Like the convex rhombic triacontahedron it has 30 rhombic faces, 60 edges and 32 vertices.

<span class="mw-page-title-main">Excavated dodecahedron</span>

In geometry, the excavated dodecahedron is a star polyhedron that looks like a dodecahedron with concave pentagonal pyramids in place of its faces. Its exterior surface represents the Ef1g1 stellation of the icosahedron. It appears in Magnus Wenninger's book Polyhedron Models as model 28, the third stellation of icosahedron.

<span class="mw-page-title-main">Icosahedron</span> Polyhedron with 20 faces

In geometry, an icosahedron is a polyhedron with 20 faces. The name comes from Ancient Greek εἴκοσι (eíkosi) 'twenty', and ἕδρα (hédra) 'seat'. The plural can be either "icosahedra" or "icosahedrons".

References