 Jali are pierced stone screens with regularly repeating patterns . They are characteristic of Indo @-@ Islamic architecture , for example in the Mughal dynasty buildings at Fatehpur Sikri and the Taj Mahal . The geometric designs combine polygons such as octagons and pentagons with other shapes such as 5- and 8 @-@ pointed stars . The patterns emphasized symmetries and suggested infinity by repetition . Jali functioned as windows or room dividers , providing privacy but allowing in air and light . Jali forms a prominent element of the architecture of India . The use of perforated walls has declined with modern building standards and the need for security . Modern , simplified jali walls , for example made with pre @-@ moulded clay or cement blocks , have been popularised by the architect Laurie Baker . Pierced windows in girih style are sometimes found elsewhere in the Islamic world , such as in windows of the Mosque of Ibn Tulun in Cairo . 
