On the picture: Close-up of the border(s) of the ‘mihrab’ (prayer niche, which indicates the direction of Mecca).
The niche is completely executed in glazed tiles.
From right to left: a border with stylised flowers and leaves; a border showing elegant calligraphy; a border with a muqarnas (stalactite) decoration, similar to stonecraft work, and a border inspired on the looks of the ‘kündekari’ woodwork technique.

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