In both cases we deal with geometric constructions. In Islamic art we have precise geometric
constructions using segments and sometimes circular shapes. The segment is a base element of the
construction. In cosmatesque as well as in Byzantine art the base elements are triangles, rectangles,
squares, discs, and rhombi. These elements are used to assemble the whole ornament. Although in
Islamic art in the Maghreb we also have such elements, these are a side effect of the geometric
constructions of complicated constellations of stars and rosettes. Simply, if we have a star or rosette
pattern we have to fill the space between the lines. In a cosmatesque we create a skeleton of the
ornament, then we inlay in the empty spaces some triangular or rectangular blocks filling spaces between them,