Kayseri Cifte Madrasah Gevher Nesibe
Above a door of the Cifte Madrasah Gevher Nesibe hospital, a muqarnas with a special set of two non-standard building units has been realized. The set creates space within the square surface of the underlying layer for a smaller building unit on the next layer. As a result, the surface of a standard square is doubled in height.
Harmsen and Krömker describe this extraordinary unit because their software did not recognize its geometry.