Islamic art is famous for its complex geometric patterns, often used to decorate mosques, palaces, and manuscripts. Because traditional Islamic belief often discourages the depiction of sentient living beings (aniconism), artists turned to calligraphy, floral motifs (arabesque), and geometry to express the infinite nature of God. These patterns are based on repeating circles and squares, creating intricate stars and polygons that can expand infinitely. One of the most famous examples is the Alhambra in Spain, where the walls are covered in 'girih' tiles—a set of five tile shapes used to create highly complex patterns. These designs are not just decorative but mathematical masterpieces; modern researchers have discovered that some medieval Islamic artisans used 'quasi-crystalline' geometry, a concept not fully understood by Western mathematicians until the 1970s.