Frieze group 6 of 7, p2mg: Conway's spinning sidle, point group 2mm, 4 operations per period, orbifold 2*∞. It is the strip of wallpaper group pmg.
Molecular point groups with their operations and character tables, the 230 space groups with a cell builder, and the 17 wallpaper and 7 frieze groups drawn live. The tool needs JavaScript, and WebGL2 for the 3D views; these are the pages it offers: