this graphic chart was made in 2003 but it's pretty nice illustration of all 17 wallpaper groups http://www.math.columbia.edu/~bayer/symmetry/wallpaper/Wallpap

this graphic chart was made in 2003 but it's pretty nice illustration of all 17 wallpaper groups http://www.math.columbia.edu/~bayer/symmetry/wallpaper/WallpaperChart.pdf http://www.math.columbia.edu/~bayer/symmetry/wallpaper/Wallp... there is also "geometry and the imagination" whose authors include John Conway (Princeton ) and fields medalist Bill Thurston http://www.math.dartmouth.edu/~doyle/docs/gi/gi.pdf http://www.math.dartmouth.edu/~doyle/docs/gi/gi.pdf