These designs are based on the nine choirs of angels as proposed by Pseudo-Dionysius the Areopagite, and on the visions of Saint Hildegard of Bingen.
The light radiates from the centre upwards, downwards, to the right and to the left. This irradiation of light captures the viewer’s eye and leads it to the point of greatest luminosity. This gives the form of the Seraphim a certain presence, as if the viewer were being observed from the centre.
Pseudo-Dionysius Areopagite describes the wings of the Seraphim as pointing upwards, to the sides and downwards. The reference to the three pairs of wings of the Seraphim is found in the two curves that crown the form, the two horizontal strokes to the left and right of its centre, as well as in the three pillars of light that support the form.
The three columns at the base of the design and the two curves in the upper third also point down. Since the Seraphim reflect God’s charity, they refer to how God’s charity and love descend to humanity through this choir of the heavenly hosts.