The hararet is not a dim spa. It is a hard, bright stone chamber — floor, walls and the octagonal göbek taşı cut from Marmara and Afyon white marble, grey veins running in parallel bands through every surface. Light enters only through star- and hexagon-shaped glass oculi punched into the dome, the fil gözü, landing as cut-edged shafts on wet stone.

This system takes that room literally. Warm marble ground, grey vein as the working color, and İznik cobalt, copper turquoise and Armenian-bole red used the way tile is used: bordered, panelled, never scattered. Arabic calligraphy carries the display voice; Latin text sits in sharp serifs, like an engraved plaque.