Wallpaper group 4 of 17, pg: a rectangular lattice, point group m, 2 operations per cell, orbifold ××. Written p1g1 in full.
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: