re: Buildings in Iraq.
Islamic civilization has always had a highly advanced architectural tradition, expanding on Greek and Roman techniques to create great arches and domes spanning wide areas. The highly intricate and interlocked geometrical decorations have also influenced western artists. Many of the tilings and tesselations have been incorporated into the work of popular Dutch artist Maurits Escher, who studied them as a youth. A study of his work, which is widely available in the west, will show you some of the basic themes.