Motifs. Although the decorative arts of Islam are sometimes referred to as the "minor arts," they in fact express much of the genius of Muslim art. The artist working for a Muslim patron had to conform to the Muslim standards for religious art if his production was to be displayed in a religious institution. Because of the prohibition on portraying people and animals, Islamic decoration consists basically of three major motifs: the geometrical, the vegetal, and the calligraphic. Of these, the geometric is by far the most common, with plant decorations or calligraphy usually serving as embellishments. Yet, occasionally plant decoration has been quite important, and calligraphy is usually present in some measure. Muslim geometric decoration tends to consist of complex webs of interlocking lines, which are more often straight than curved, producing an angular effect in the designs. Rounded lines are used especially...