CARRARA This Tuscan column has a 240mm shaft diameter, it has a pleasing shape with a subtle curve of entasis to the shaft. This shape is put into the design to adjust the appearance where normal taper would make the column appear weak at the upper part of the shaft. The formula for entasis has been brought down from ancient Greece where it is clearly seen on the Parthenon in Athens. The Carrara column is often used in pergolas and verandahs and colonnades. There is a fine balance between diameter and height.