Johnson solid

A Johnson solid is a convex polyhedron whose faces are all regular polygons.

[7] Johnson (1966) published a list including ninety-two Johnson solids—excluding the five Platonic solids, the thirteen Archimedean solids, the infinitely many uniform prisms, and the infinitely many uniform antiprisms—and gave them their names and numbers.

From there, a series of prefixes are attached to the word to indicate additions, rotations, and transformations:[10] The last three operations—augmentation, diminution, and gyration—can be performed multiple times for certain large solids.

[10] The last few Johnson solids have names based on certain polygon complexes from which they are assembled.

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.

[8][11] The other Johnson solids are composite polyhedron because they are constructed by attaching some elementary polyhedra.

[12] As the definition above, a Johnson solid is a convex polyhedron with regular polygons as their faces.

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".