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
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