The choir is flanked by double aisles with slender intermediary piers supporting the vaults of inner and outer aisles. These supports are formed around a central cylindrical core (diameter?) flanked by eight colonnettes, the major one supporting the transerse arches and the thinner ones supporting the diagonals. The thinner shafts are formed of separate sticks of stone, not coursed in the with main body of the pier. Built my Master Thomas c 1230s-40s.
It should be remembered that these slender units carry the weight of the intermediary uprights of the flying buttresses system. We begin to understand why Master Renaud did his best to make the flying buttresses of the choir as light as possible.