In what ways did islamic art and literature show diversity, and what important trait do they have in common?

The most distinguishing trait of Islamic art and literature is Unity in Diversity. As Islamic culture was  influenced by encounters with other cultures and religions, like those of the Byzantine empire, Jerusalem as well as local trends in Syria, Jordan and Palestine, its art and literature shows this influence in its diverse forms. For example, the Octagonal Dome of the Rock, which was inspired from Byzantine churches. Whereas the Safavid arts showed influences from Chinese blue and white wares in their pottery. Islamic literature was also inspired and adapted from stories of diverse cultures, like the Turkish, the Persian as well as Indian.
Common traits in art included calligraphy on different mediums,  geometrical motifs, domes and minarets. In literature, the absence and intolerance of 'fiction' as advised by the Quran was a common trait. This was because fiction has been characterized as lying  by the Quran. However, mysticism and spiritual poetry strongly characterize the Islamic literature.