Bīmāristān al-Qaymarī: Plaster Decorations II

The two surfaces of the large barrel vault of the south īwān are ornamented like a carpet with a border and a center. The border is a kind of astragal, the center a huge roundel; the Arabs call them mirror, mirāyā, or dish, ṣaynīyyā. The roundel has twenty-four appendages. These appendages and the circle from which they radiate are higher in relief than the middle, and their elements are late Byzantine acanthi.

Ernst Herzfeld. Damascus, Studies in Architecture III. Ars Islamica XI-XII 1946 (p. 1-71).