On the picture: A close-up of the borders of the mihrab, which are similar to those of the prayer niche in the Yeşil Mosque. From right to left: an elegant calligraphy in sülüs script; a border having a muqarnas (stalactite) decoration, similar to stonecraft work; and a border inspired on the looks of the ‘kündekari’ woodwork technique.
This is an example of the Islamic passion for relating areas and objects of disparate size and purpose through their decoration.

Sülüs (from Arabic: ثلث‎ ṯuluṯ "one-third"), also referred to as ‘thuluth’, is a script variety of Islamic calligraphy invented in Persia, which made its first appearance in the 11th century AD. The straight angular forms of the older Kufic script were replaced in the new script by curved and oblique lines. In Sülüs, one-third of each letter slopes, from which the name (meaning "a third" in Arabic) comes. It is a large and elegant, cursive script, used in medieval times on mosque decorations.

In the ‘kündekari’ technique pieces of wood of different sizes are worked separately, and then assembled (like a big jigsaw puzzle), without using any glue, split pin or nail. The technique was used in Egypt, Syria and Anatolia from the 11th century on, and became a major art form in Seljuk and late-Seljuk times (13th-15th century).

Correspondent: J.M.Criel, Antwerpen.
Sources: ‘Vakıf Abideler ve eski Eserler’ - Vakıflar Genel Müdürlüğü III, Ankara 1983 ; Wikipedia
& ‘Islamic Architecture: Ottoman Turkey’ (Godfrey Goodwin) – London 1977 .