Or. The beautiful, intricate, detailed, 3D-like elements from the Islamic/Persian architecture.
A snapshot from the (current) Wikipedia entry:
An architectural ornamentation reminiscent of stalactites, muqarnas developed around the middle of the 10th century in northeastern Iran and almost simultaneously — but seemingly independently — in central North Africa; they take the form of small pointed niches, stacked in tiers which project beyond lower tiers, commonly constructed of brick, stone, stucco, or wood, clad with painted tiles, wood, or plaster, and are typically applied to domes, pendentives, cornices, squinches and the undersides of arches and vaults.
[...]
Muqarnas display radial symmetry based upon N-gonal symmetry. The number of unique tiles possible is derived from N = N/2 - 1. Larger N values result in thinner muquarnas tiles. There are an unlimited number of muqarnas tile sets given the wide variety of tile profile design possibilities. Computer graphics and fabrication today allow the design and production of novel muqarnas compositions not found in the historical record.
