Besides there are so many studies about geometric decoration applications, which exist especially in architectural works in almost all around the Islamic geography; these studies are insufficient about considering the alteration of their geometric compositions according to their geographic diversity and mathematical progress throughout the Islamic history. This situation is in contradiction with the wealth of geometric decoration on the architectural works that they possess. Aim of this article is to call attention to methods of pattern production and to conduce to make compositional analyses in next scientific studies, which includes geometric pattern, with reference to these production principles. This article, in addition, aims to flash on different analyses on unit cells that have hexagonal and square fictions, which applied in classical Ottoman artworks. In this article, it is presented that the geometric pattern applications, which have rich diversity in also artworks of Ottoman classical period, applied where and in which compositions. It is worked out, by comparing to pre-Ottoman period, how the pattern applications codified. It is included analyses of some interesting patterns, which were composed with reference to the unit cells, through Şehzade, Süleymaniye and Selimiye Mosques