On Talaa Kebira, directly opposite the Bou Inania madrasa, a building presents a curious facade: thirteen wooden beams jut out horizontally from windows in the upper story, making no obvious architectural sense. This is Dar al-Magana — the House of the Clock — a fourteenth-century hydraulic water clock commissioned by Sultan Abu Inan to call students at the madrasa across the road to prayer at the correct hours.
The mechanism itself has not functioned since the early centuries of its existence; nobody today fully understands how it worked. Several scholars have attempted to reconstruct the mechanism from contemporaneous descriptions, but the results are disputed. The building is not open to visitors but the facade alone, spotted mid-medina walk, is one of those details that makes Fez unlike anywhere else.