Wallpaper group 12 of 17, p4g: a square lattice, point group 4mm, 8 operations per cell, orbifold 4*2. Written p4gm 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: