muqarnas مقرنص

How do you set a round dome on top of a square room without the corners caving in?

One answer is muqarnas: a honeycomb of tiered niches that corbels out layer by layer across the corner.

Each tier steps forward over the one below, carrying the curve of the dome down to the square walls.

Carved in stone, brick, stucco, or wood, its hundreds of facets catch rising light and dissolve heavy mass into shadow.

Emerging in tenth-century Iran and Iraq, it crowned portals and domes from the Alhambra in Granada to Isfahan.

Its cousins: the squinch in Iran, the pendentive in Istanbul, and the Gothic fan vault in England.

Muqarnas. A tiered honeycomb of niches that bridges a square room to a round dome.