Pair of quadrangular panels of unknown origin, in white marble, with geometric inlays in serpentine and Lunense red marbles. Similar panels can be found both in the bell tower and Cathedral exterior. They were probably part of the series of marble panels originally situated beneath the rooftop walkways on the sides of Santa Maria del Fiore, decorated with similar decorations of “exercises in compass and squares”. Between 1938 and 1958 there were many restoration interventions on the external marble coverings of the Duomo, which led to replacement of some elements. The largest of these two slabs is rectangular, marked by groove separating two parts: in one there is a solar motif, in the other an inlaid braid motif. The second slab is square and is decorated with a star and floral design.