a study of geometric pattern in architectural ornament in gonabad, malek-zuzan and foroumad mosques

in early islamic era, architecture in khorasan was followed the common features of early islamic architecture style; such as simplicity in construction and ornament. in the later periods, especially in seljuq dynasty, the application of brick, stucco, tiling and inscription had been used more in architectural ornament. then, in the short period under the khwarizmshahid dynasty in khorasan, two-iivan mosques had been built with the emphasis of architectural ornament. gonabad, malek zuzan and foroumad mosques are three famous two-iivan mosques in iran which have outstanding geometric ornament. in this research we survey design methods in geometric pattern in architectural ornament in these mosques of khwarizmshahid period. and also we try to explain the probable design method of selected samples with the application of common instruments at the time of built; ruler and compass. the connection between scientific centers and islamic governments was so prominent. famous scientists had studied in scientific centers in islamic world and their scientific achievements flourished islamic art and civilization. geometry was one of the knowledge which had direct connection with architecture and architectural ornament. “on the geometric constructions necessary for the artisan” is one of the reliable sources in the field of practical geometry in islamic civilization which written by abu’l-wafa buzjani- iranian mathematicians and astronomer in the 4th century- in arabic, international language in islamic world at that time. in this book, buzjani describes the ways of geometrical designs with the common instruments. with adaptation by geometric design methods in two-ivan mosques, gonabad, malek-zuzan and faruomad, with the buzjanis’ dissertation, “on the geometric constructions necessary for the artisan”, in this research we try to suggest appropriate methods for design and construct of geometric architectural ornament with the common instruments and geometric theorems at the time of built. in order to analyze, we cited by the buzjani’s dissertation which is one of the most important references in islamic mathematics. buzjani explains common design instruments and methods in geometric construction and theorems. the result shows that these geometric patterns were designed based on accurate substructure with the architectures’ knowledge of geometry. we can see that these complex patterns are drawn based on accurate geometric divisions and design. and it is implied that architectural ornament is one of the most important sources to apply geometry in the practical filed and they like a reliable evidence of scientific achievement of each period. by comparing the geometric theorem and common instruments in the buzjani’s book with the methods which we suggested for design of the architectural ornament of these mosques in this paper, it shows that architects and artisans have knowledge in geometry for their design and also they were expert in this filed as well as art and architecture. so, it is demonstrated that there was a deep connection among artisans, architects and mathematicians in the islamic world, especially in early islamic period.