This boss is a masterpiece of woodwork. Each piece is separately crafted, the panels each fitting into grooves along the sides of the bands. The whole is then kept in place by the insertion of the central star-shaped panel which is then held in place from behind by an iron pin fixed with a wedge through a slot. This keeps tension on the star towards the base of the dome, which in turn holds all the separate pieces in place. The remarkable thing about it is that each small piece has been carved completely in three dimensions. Achieving this sort of geometry in two dimensions is tricky; to achieve it in three is enormously more so.
Similar elements of construction, but not as complicated, are found on the sides of the minbar of the mosque of the Amir Qijmas al-Ishaqi dating from 1479-1481 (Henri and Anne Stierlin, Splendours of an Islamic World, London, 1997, pp.66-7, and p.69). All the features found on the present boss are encountered there: the curved panels within the geometry, the multiple ribbing of the strapwork, the relative simplicity of the flat inlaid ivory details within each piece, the green-stained ivory in details, and the appearance of a boss at the centre of the whole design. In the Amir Qijmas example the boss is a single piece, whose surface is covered with wood and ivory geometric marquetry. Related but simpler work is found on the minbar of the mosque of sultan al-Ashraf Barsbay dateable to 1432.
This boss, particularly in its use of the curves within the geometry, seems to have been a specific style only used in a very few commissions. It is noticeably different from the styles of the minbars of Sultan Qaitbay, the Sultan for whom Amir Qijmas looked after the royal stables. Both the sultan's minbars, that in the northern cemetery (http://archnet.org/library/images/one-image.jsp?location_id=4764&ima ge_id=113661), and that of the minbar originally in his mosque in central Cairo (Tim Stanley, Palace and Mosque, London, 2004, pp. 100-101). Those are more traditional, with only straight lines separating the panels, and with carved single ivory panels used in the inlay rather than the fine stellar polygons found here.