 The circle symbolizes unity and diversity in nature , and many Islamic patterns are drawn starting with a circle . For example , the decoration of the 15th century mosque in Yazd , Iran is based on a circle , divided into six by six circles drawn around it , all touching at its centre and each touching its two neighbours ' centres to form a regular hexagon . On this basis is constructed a six @-@ pointed star surrounded by six smaller irregular hexagons to form a tessellating star pattern . This forms the basic design which is outlined in white on the wall of the mosque . That design , however , is overlaid with an intersecting tracery in blue around tiles of other colours , forming an elaborate pattern that partially conceals the original and underlying design . A similar design forms the logo of the Mohammed Ali Research Center . 
