A small howz in a mosque in Tehran shaped in the traditional form of two squares, one rotated 45 degrees.
In traditional Persian architecture, a howz (pool) is a centrally positioned symmetrical axis pool. If in a traditional house or private courtyard, it is used for bathing, aesthetics or both. If in a sahn of a mosque, it is used for performing ablutions. A howz is usually around 30 centimetres (12 in) deep. It may be used as a "theatre" for people to sit on all sides of the pool while others entertain.