Arabesque in Islamic art is often used to symbolize the supreme, indivisible and infinite nature of God (Gloria k Fiero). One of the most recognized forms of Islamic artwork is the introduction of the pile rug, better known as the oriental rug, with an endless assortment of patterns, colors and sizes. These rugs were considered with religion in mind and were referred to as a prayer rug, which would provide a clean place to pray). Islamic art has focused on pattern design and Arabic calligraphy, rather than figures, because many Muslims fear that depictions of the human form, considered worship, are a sin against God and outlawed in the Quran. Today modern art historians criticize Islamic art, due to the diversity of regions and cultures, which contributed their influences and styles, and are an overall fusion of past cultures such as Roman, Christian, Byzantine and Arabic.