Final answer:
An iwan plan mosque and a hypostyle-plan mosque have different architectural layouts. The iwan plan mosque has multiple iwans that open to a courtyard, while the hypostyle-plan mosque has a main prayer hall with columns. The qibla iwan in the Friday Mosque at Isfahan points toward Mecca.
Step-by-step explanation:
An "iwan" plan mosque and a hypostyle-plan mosque have different architectural layouts. In a hypostyle-plan mosque, the main prayer hall is characterized by a forest of columns supporting the roof. On the other hand, an iwan plan mosque has several iwans, which are vaulted spaces that open on one side to a courtyard. These iwans serve as prayer halls or entrances to other spaces within the mosque.
For example, the Friday Mosque at Isfahan is a four-iwan plan mosque. The iwans in this mosque are located on each side of the central courtyard and are enclosed on three sides, opening only to the courtyard. The iwan that points toward Mecca is known as the qibla iwan. In the case of the Friday Mosque at Isfahan, the qibla iwan is located on the southern side of the courtyard and is flanked by two cylindrical minarets.