The World of 3-dimension structures

Equi-polyhedron

In modular origami, you can assemble several units to
make 3-dimensional-structures without using glue. You can find these solids in the biology or chemistry textbook when you study.
It is called the 'Equi-polyhedron'. There are 9 kinds that have the congruent polygonal shape surfaces. The same number of surfaces is combined at every point.
Here I'd like to show you polyhedrons that have congruent polygonal-shape faces and have no bump on their surface. There are 5 of them. You can assemble them with appropriate numbers of polygonal shapes in Origami.

Tetrahedron (4 equilateral triangles)

Hexahedron (6 squares)

Octahedron (8 equilateral triangles)

Dodecahedron (12 pentagonal shapes)

Icosahedron (20 equilateral triangles)

3-dpolyhedron