Note the extensive use of diacritical marks which are normally omitted from standard Persian or from Kufic. Because of the strong contrast between vertical and horizontal forms it was frequently used as a border to both the eivan and the mihrab as described below.
Enormous inventiveness has gone into the design of the inscriptions for which it is used and it is generally used in places where some kind of connection is wanted, typically round the edge of an eivan or mehrab, such as the famous one in the Shekh Lotfallah Mosque, or to mark the transition between drum and dome such as can be seen in the Royal Mosque. One particularly effective treatment, which shows its versatility is in the famous stucco mehrab erected by the Il Khanid Sultan Oljeitu in the Friday Mosque at the start of the fourteenth century.
The vertical lines can be seen as symbolising the relationship between God and man while the horizontal movement as a symbol of the relationship between man and the world. It was thus natural to use such a script as a temenos or boundary, to divide and direct man's attention into the fourfold path of individuation and gnosis.