sentences:  The walls are reinforced by chains made of small stone blocks.The building, the central plan of which was consciously repeated in the basilica of San Vitale in Ravenna and served as a model for the famous Ottoman architect Mimar Sinan in the construction of the Rüstem Pasha Mosque, has the shape of an octagon inscribed in an irregular quadrilateral.It is surmounted by a beautiful umbrella dome in sixteen compartments with eight flat sections alternating with eight concave ones, standing on eight polygonal pillars.