"""Ardashir's palace is a monumental structure of rough stone and gypsum mortar, built without fortifications, after his accession. Rectangular halls in the palace were roofed with domes constructed of rubble and gypsum mortar. This exceptionally strong and resilient dome rested on a transitional zone that transformed the rectangular walls of the room into a circular base for the cupola through the use of a small arch, the squinch, built above the four corners of the walls."
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