Wikipedia:POTD column/October 26, 2006



Symmetry is a foundational concept in several sub-disciplines of mathematics, particularly geometry and abstract algebra. The rotation symmetry group of the tetrahedron (shown here) associates the 12 different orientations of a tetrahedron with two kinds of spatial rotation that rearrange those orientations: a 120° rotation around each of the 4 vertices (reddish arrows), and 180° rotation through opposite edges (blue arrows). Diagrams illustrating the symmetries of a mathematical object in this format are called cycle graphs.

Illustration credit: Debivort Archive - More featured pictures...