The interior of the mosque is dominated by a fantastic cupola suspended on a complex system of arches over an octagon inserted into a square base whose relatively plain archways from a diaphanous light-filled screen behind counterparts inside. At the centre, supported by a series of polylobate arches set up over the summits of those below, stand the dazzling motif of the great dome derived from mosaic prototype in the mosque at Cordoba. Subtly choreographed, the dappled light pours in through alternating arches and external windows, at one time embellished with stucco latticework glazed with coloured glass that must have made the interior still more vibrant and conferred on the semi-darkness a spellbinding atmosphere, perhaps still further enhanced by the waters babbling from the fountain below. The evocative ensemble of intersecting arches, deriving, like the cupola, from caliphate models,is reworked here in view of 'anti-structural' experiments in vogue in the Taifa kingdoms. This approach might well have influenced the otherwise ascetic Almoravid and resulted in elaborate formal solutions that apparently anticipate the analogous Baroque invention of Guarino Guarini, where, however, the problems of load-bearing are resolved in a structurally far more complex fashion.