The Seventeen Groups
Each of the groups in this section has two cell structure diagrams, which are to be interpreted as follows:
| a centre of rotation of order two (180°). | |
| a centre of rotation of order three (120°). | |
| a centre of rotation of order four (90°). | |
| a centre of rotation of order six (60°). | |
| an axis of reflection. | |
| an axis of glide reflection. |
On the right-hand side diagrams, different equivalence classes of symmetry elements are colored (and rotated) differently.
The brown or yellow area indicates a fundamental domain, i.e. the smallest part of the pattern that is repeated.
The diagrams on the right show the cell of the lattice corresponding to the smallest translations; those on the left sometimes show a larger area.
Read more about this topic: Wallpaper Group
Famous quotes containing the words seventeen and/or groups:
“When you are seventeen you aren’t really serious.”
—Arthur Rimbaud (1854–1891)
“Trees appeared in groups and singly, revolving coolly and blandly, displaying the latest fashions. The blue dampness of a ravine. A memory of love, disguised as a meadow. Wispy clouds—the greyhounds of heaven.”
—Vladimir Nabokov (1899–1977)