Islamic art encompasses visual arts produced by Islamic populations from the 7th century onwards, including fields as diverse as calligraphy, painting, glass, ceramics, and textiles. It is difficult to define because it covers many lands over 1400 years and is not specific to a single religion, time period, place, or medium. Calligraphic design featuring religious and poetic inscriptions is ubiquitous in Islamic art. Notable achievements include ceramics and tilework, which were used to decorate the interiors of early grand Islamic buildings in the absence of wall paintings.