Talk:Point groups in two dimensions
It has been difficult for me to find good introductory material on the two-dimensional point groups, though I have had more success with searching for "rosette groups". I have found:
[http://www.math.ttu.edu/~drager/Classes/10MathCamp/handouts04.pdf Geometric Transformations and Wallpaper Groups: Symmetries of Geometric Patterns (Discrete Groups of Isometries)] is the best I could find. It's at 2010 Math Camp by Prof. Lance Drager.
It contains a proof that there are two infinite families of rosette groups: cyclic and dihedral.
It might also be nice to create some illustrations of elements in the group in action. Shall I do so? I'd make an illustration of rotation and reflection of a simple polygon - triangle or square or pentagon.