Another architect Badi al-zaman-i Tuni may have been involved in its early design. Standing in the public square, or Maidan, the entrance-iwan (gateway) to the mosque takes the form of a semicircle, resembling a recessed half-moon and measuring 27 meters in height, the arch framed by turquoise ornament and decorated with rich stalactite-like tilework called muqarnas, a distinct feature of Persian Islamic architecture. At the sides rise two minarets, 42 meters high, topped by beautifully carved, wooden balconies with muqarnas running down the sides. In the middle, in front of the entrance, stood a small pool and a resting place for the horses, and inside the worshipers found a large marble basin set on a pedestal, filled with fresh water or lemonade. This basin still stands as it has for four hundred years, but no longer serves the function of providing refreshments to the worshipers at the Friday prayers. The distinct feature of any mosque is the minaret, and the Masjed-e Shah has four.