ساختار و ویژگی‌ کتیبه‌های کوفی تزئینی(گل‌دار، گره‌دار)در دوره سلجوقی و ایلخانی

 
From the third century AH Kufic calligraphy appeared in architectural works and until about the seventh century AH, various species of that were formed in different regions and areas of Iran, among which are the cities of Isfahan, Kerman and Khorasan. In a general classification, they can be described as "decorative Kufic". This kind of script is stable and sturdy in style, and its geometric structure is based on smooth, angled and long drawn strokes. It includes scripts such as banna-i Kufic (Square Kufic) and Moaqqeli Kufic, Gereh-dar Kufic (Knotted Kufic) and Gol-dar Kufic (Floral Kufic). These species had the most adaptability and harmony with architectural spaces in terms of implementation, beauty as well as materials, and due to their special flexibility, variable geometry, different size and thickness of their letters, length, combination with floral and geometrical patterns and other capabilities, provided ground for the formation of various kinds of decorative Kufic.
The main reason for diversity in Kufic calligraphy in architecture is its diversity in spaces and various architectural surfaces. Kufic calligraphy gets its identity from the dimension, size and the space in handwriting, so it is not possible to find rigid and fixed geometric rules for it.
According to the decorative Kufic inscriptions in the historical buildings of Iran, we can divide the components of the Kufic calligraphy into three major parts of written, geometric and vegetal systems.
Written system: It is readable texts and writings, either letters or words apart from geometric and non-geometric decorations, which are most important as content and semantic parts of inscriptions. It is cansidentd on the following lower seat of the Tines.
This part of inscription, in regard to both content and formality, is considered the main body of the line and cannot be removed from the inscription space. The character and general form of Kufic inscriptions depend on the type of writing system. If the line has soft and delicate curves, the engineering system as well as herbaceous system should be designed in accordance with the same softness and elegance, in other words homogeneous designs should be selected to avoid non-convergence in letters and decorative elements.
Geometric system: the second part of the decorative Kufic category consists of geometric and knotted motifs. These motifs are often placed in the middle of the vertical axis of the handled words, Alfie, Lam, Ta, and Za. They connect loops between the written system and vegetal system.
Vegetal system: the upper part of the letters and words in the inscriptions is allocated to vegetal designs. The two best known types of these motifs, Eslimis and khatais, derived from natural elements and abstract motifs with twisting and abstract motions can move freely in the space of inscription. Extending and expansion of these designs depend on the space of the inscription.
The only script in which the structures and design may combine in connection to the main body of the line is Kufic script in the inscription. This script, with its defined rules, comes more from written system rather than vegetal or geometric condition and create new compositions. The structure of decorative Kufic calligraphy is a geometrical one but in the meantime flowing and extendable to all directions.
There is no prescribed form of writing in teaching decorative Kufic calligraphy, but in a systematic written system the arrangement, combination and amount of whiteness and blackness are observed as in other inscriptions. In geometrical and vegetal systems, because of lines, transversal, horizontal, vertical, diagonal and circular tractions, the most motions and creations are applied by the designees.      
 Most of the examples, Gereh-dar Kufic (Knotted Kufic) and Gol-dar Kufic (Floral Kufic), can be seen in the brickwork of the Seljuk period and the stucco of the Ilkhanid mihrabs. The brickwork inscriptions of the mosque of Malek Zozan of Khorasan, the Khorgerd School, the Kerman Minaret and the Bastam stucco inscriptions, the inscription of the mosque of Orumieh, the inscription of the Mihrab of the Tabriz Jame- Mosque, are among these works.
The question is what the components of decorative Kufic inscriptions are and what are their capabilities and attributes?
 Using visual and library resources and descriptive-analytic methods, this article aims at answering to the following question: how geometric structure of the decorative Kufic could be adapted to each level and size? It also investigates the special features of the Knotted Kufic and Floral Kufic, and explains three different types of writing, geometric and vegetal design systems for the first time in Kufic calligraphy framework.