The earliest attempts to provide variety took advantage of the strong clear light of Iran to highlight the textures and patterns which could be formed with brickwork. The minaret of Chehel Dokhtaran, built in 1107 shows some of the incredible variety of patterns which could be achieved as well as demonstrating the way in which script could be formed with the bricks.
The use of glazed terracotta inserts to reproduce passages from the Qura'n, as shown in the thuluth decoration on the Ziar minaret, demonstrates a development of the simple glazed brickwork mosaic and can be thought of as the start of a long tradition of mosaic tilework, culminating in the elaborate tilework of the Safavids.
The sequence of pictures demonstrates the transition from raised brickwork and terracotta inserts through the use of polychrome glazes to accentuate patterns into the full-blown use of glazed terracotta inserts to reproduce the intricacies of Qura'nic script.