“The Grammar of Ornament” by Owen Jones (1809 – 1874) is a work in which the author collects elements of design and typical motifs from a wide range of cultures. A site dedicated to the book can be found here and a full digitised version at The Grammar of Ornament: University of Wisconsin Digital Library. There is a also set of images from The Grammar of Ornament on Flickr. Since many of the designs are repeating patterns, they can be used to teach the concept of wallpaper group symmetry (and, by extension, space group symmetry); Martin von Gagern has used them to make some very beautiful illustrations of these groups on his Morenaments page. Some of the motifs are also used to illustrate the Wikipedia entry on wallpaper groups. I have used an Egyptian design from The Grammar of Ornament to illustrate the concept of primitive and non-primitive unit cells. Lattice points (those points in identical environments, assuming that the pattern extends infinitely) are marked using blue dots. A primitive unit cell (or, more properly, unit mesh) contains only one unique lattice point, whereas a non-primitive cell contains more than one lattice point. The choice of a non-primitive cell usually reflects the overall symmetry of the structure; here, for example, the square shape of the overall pattern can be seen more clearly from the non-primitive cell. One of the great advantages of using The Grammar of Ornament for teaching is that the patterns come from so many different ages and cultures, making it a great inclusive tool for international and multicultural classes.