TILLA-KARI (Gold – covered 3D) Medressa, located in the Registan, was completed in 1660. A prosperous period in the history of Samarkand, highlighted with the mosque’s delicate ceiling oozing gold leaf. The interesting thing here is that the ceiling that looks distinctly dome shaped because of it’s tapered design was in fact FLAT!! It seems, the 3D effect was already around in the 17th century!!