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== Naming and enumeration == {{main article|List of Johnson solids}} [[File:Triaugmented triangular prism (symmetric view).svg|thumb|An example is [[triaugmented triangular prism]]. Here, it is constructed from triangular prism by joining three equilateral square pyramids onto each of its squares (tri-). The process of this construction known as "augmentation", making its first name is "triaugmented".]] The naming of Johnson solids follows a flexible and precise descriptive formula that allows many solids to be named in multiple different ways without compromising the accuracy of each name as a description. Most Johnson solids can be constructed from the first few solids ([[Pyramid (geometry)|pyramids]], [[cupola (geometry)|cupolae]], and a [[rotunda (geometry)|rotunda]]), together with the [[Platonic solid|Platonic]] and [[Archimedean solid|Archimedean]] solids, [[prism (geometry)|prisms]], and [[antiprism]]s; the center of a particular solid's name will reflect these ingredients. From there, a series of prefixes are attached to the word to indicate additions, rotations, and transformations:{{r|berman}} * ''Bi-'' indicates that two copies of the solid are joined base-to-base. For cupolae and rotundas, the solids can be joined so that either like faces (''ortho-'') or unlike faces (''gyro-'') meet. Using this nomenclature, a [[pentagonal bipyramid]] is a solid constructed by attaching two bases of pentagonal pyramids. [[Triangular orthobicupola]] is constructed by two triangular cupolas along their bases. * ''Elongated'' indicates a [[prism (geometry)|prism]] is joined to the base of the solid, or between the bases; ''gyroelongated'' indicates an [[antiprism]]. ''Augmented'' indicates another polyhedron, namely a [[pyramid (geometry)|pyramid]] or [[Cupola (geometry)|cupola]], is joined to one or more faces of the solid in question. *''Diminished'' indicates a pyramid or cupola is removed from one or more faces of the solid in question. *''[[gyration|Gyrate]]'' indicates a cupola mounted on or featured in the solid in question is rotated such that different edges match up, as in the difference between ortho- and gyrobicupolae. {{multiple image | image1 = Parabiaugmented hexagonal prism.png | image2 = Metabiaugmented hexagonal prism.png | align = right | total_width = 350 | footer = Examples of ''para-'' and ''meta-'' can be found in [[parabiaugmented hexagonal prism]] and [[metabiaugmented hexagonal prism]] }} The last three operations—''augmentation'', ''diminution'', and ''gyration''—can be performed multiple times for certain large solids. ''Bi-'' & ''Tri-'' indicate a double and triple operation respectively. For example, a ''bigyrate'' solid has two rotated cupolae, and a ''tridiminished'' solid has three removed pyramids or cupolae. In certain large solids, a distinction is made between solids where altered faces are parallel and solids where altered faces are oblique. ''Para-'' indicates the former, that the solid in question has altered parallel faces, and ''meta-'' the latter, altered oblique faces. For example, a ''parabiaugmented'' solid has had two parallel faces augmented, and a ''metabigyrate'' solid has had two oblique faces gyrated.{{r|berman}} The last few Johnson solids have names based on certain polygon complexes from which they are assembled. These names are defined by Johnson with the following nomenclature:{{r|berman}} *A ''lune'' is a complex of two triangles attached to opposite sides of a square. *''Spheno''- indicates a wedgelike complex formed by two adjacent lunes. ''Dispheno-'' indicates two such complexes. *''Hebespheno''- indicates a blunt complex of two lunes separated by a third lune. *''Corona'' is a crownlike complex of eight triangles. *''Megacorona'' is a larger crownlike complex of twelve triangles. *The suffix -''cingulum'' indicates a belt of twelve triangles. The enumeration of Johnson solids may be denoted as <math> J_n </math>, where <math> n </math> denoted the list's enumeration (an example is <math> J_1 </math> denoted the first Johnson solid, the equilateral square pyramid).{{r|uehara}} The following is the list of ninety-two Johnson solids, with the enumeration followed according to the list of {{harvtxt|Johnson|1966}}: {{columns-list|colwidth=25em| # [[Equilateral square pyramid]] # [[Pentagonal pyramid]] # [[Triangular cupola]] # [[Square cupola]] # [[Pentagonal cupola]] # [[Pentagonal rotunda]] # [[Elongated triangular pyramid]] # [[Elongated square pyramid]] # [[Elongated pentagonal pyramid]] # [[Gyroelongated square pyramid]] # [[Gyroelongated pentagonal pyramid]] # [[Triangular bipyramid]] # [[Pentagonal bipyramid]] # [[Elongated triangular bipyramid]] # [[Elongated square bipyramid]] # [[Elongated pentagonal bipyramid]] # [[Gyroelongated square bipyramid]] # [[Elongated triangular cupola]] # [[Elongated square cupola]] # [[Elongated pentagonal cupola]] # [[Elongated pentagonal rotunda]] # [[Gyroelongated triangular cupola]] # [[Gyroelongated square cupola]] # [[Gyroelongated pentagonal cupola]] # [[Gyroelongated pentagonal rotunda]] # [[Gyrobifastigium]] # [[Triangular orthobicupola]] # [[Square orthobicupola]] # [[Square gyrobicupola]] # [[Pentagonal orthobicupola]] # [[Pentagonal gyrobicupola]] # [[Pentagonal orthocupolarotunda]] # [[Pentagonal gyrocupolarotunda]] # [[Pentagonal orthobirotunda]] # [[Elongated triangular orthobicupola]] # [[Elongated triangular gyrobicupola]] # [[Elongated square gyrobicupola]] # [[Elongated pentagonal orthobicupola]] # [[Elongated pentagonal gyrobicupola]] # [[Elongated pentagonal orthocupolarotunda]] # [[Elongated pentagonal gyrocupolarotunda]] # [[Elongated pentagonal orthobirotunda]] # [[Elongated pentagonal gyrobirotunda]] # [[Gyroelongated triangular bicupola]] # [[Gyroelongated square bicupola]] # [[Gyroelongated pentagonal bicupola]] # [[Gyroelongated pentagonal cupolarotunda]] # [[Gyroelongated pentagonal birotunda]] # [[Augmented triangular prism]] # [[Biaugmented triangular prism]] # [[Triaugmented triangular prism]] # [[Augmented pentagonal prism]] # [[Biaugmented pentagonal prism]] # [[Augmented hexagonal prism]] # [[Parabiaugmented hexagonal prism]] # [[Metabiaugmented hexagonal prism]] # [[Triaugmented hexagonal prism]] # [[Augmented dodecahedron]] # [[Parabiaugmented dodecahedron]] # [[Metabiaugmented dodecahedron]] # [[Triaugmented dodecahedron]] # [[Metabidiminished icosahedron]] # [[Tridiminished icosahedron]] # [[Augmented tridiminished icosahedron]] # [[Augmented truncated tetrahedron]] # [[Augmented truncated cube]] # [[Biaugmented truncated cube]] # [[Augmented truncated dodecahedron]] # [[Parabiaugmented truncated dodecahedron]] # [[Metabiaugmented truncated dodecahedron]] # [[Triaugmented truncated dodecahedron]] # [[Gyrate rhombicosidodecahedron]] # [[Parabigyrate rhombicosidodecahedron]] # [[Metabigyrate rhombicosidodecahedron]] # [[Trigyrate rhombicosidodecahedron]] # [[Diminished rhombicosidodecahedron]] # [[Paragyrate diminished rhombicosidodecahedron]] # [[Metagyrate diminished rhombicosidodecahedron]] # [[Bigyrate diminished rhombicosidodecahedron]] # [[Parabidiminished rhombicosidodecahedron]] # [[Metabidiminished rhombicosidodecahedron]] # [[Gyrate bidiminished rhombicosidodecahedron]] # [[Tridiminished rhombicosidodecahedron]] # [[Snub disphenoid]] # [[Snub square antiprism]] # [[Sphenocorona]] # [[Augmented sphenocorona]] # [[Sphenomegacorona]] # [[Hebesphenomegacorona]] # [[Disphenocingulum]] # [[Bilunabirotunda]] # [[Triangular hebesphenorotunda]] }} Some of the Johnson solids may be categorized as [[elementary polyhedra]]. This means the polyhedron cannot be separated by a plane to create two small convex polyhedra with regular faces; examples of Johnson solids are the first six Johnson solids—[[square pyramid]], [[pentagonal pyramid]], [[triangular cupola]], [[square cupola]], [[pentagonal cupola]], and [[pentagonal rotunda]]—[[tridiminished icosahedron]], [[parabidiminished rhombicosidodecahedron]], [[tridiminished rhombicosidodecahedron]], [[snub disphenoid]], [[snub square antiprism]], [[sphenocorona]], [[sphenomegacorona]], [[hebesphenomegacorona]], [[disphenocingulum]], [[bilunabirotunda]], and [[triangular hebesphenorotunda]].{{r|johnson|hartshorne}} The other Johnson solids are [[composite polyhedron]] because they are constructed by attaching some elementary polyhedra.{{r|timofeenko-2010}}
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