Rafael de la Hoz conclude that Cordovan architecture shows preference for the use of the Octagon in its constructions. This way, the constructive basis of the universally known as "Cordovan Vault", which was precisely invented in the Mosque (the most emblematic monument in Cordoba), has an octagonal ground plant. As you can see in the pictures below, the most sacred facility in the construction, the Mihrab, is octogonal and the floor of the Mosque is made of Cordovan rectangles.
The proportion is displayed also in the Arcs of the Mosque and in Alhaken's Door, outside of the building.
It is deduced that Cordovan proportion's use is a basic element in the cordovan Caliph architecture and in the rear architecture. However, it has been also seen in previous constructions such as the pyramids of Egypt, or in other more unknown worlds such as the Teotihuacan and in it is been used in monuments and modern architecture buildings in Cordoba, Spain and all over the world.
It appears in Christian temples, churches and cathedrals, Jews synagogues, Muslims Mosques and many different kind of buildings.