The process of glassmaking first requires collecting a mass of molten glass at the end of the cane. The craftsman then rotates its metal rod continuously to obtain a homogeneous element. He then alternates between blowing the glass, cooling it, reheating it in the oven, and adding more molten glass. Various pliers allow the glassmaker to give the mass the desired shape. Speed imperatives inherent to production on a larger scale do not exclude the use of this technique. It serves, among other things, for manufacturing precious and rare pieces, such as multi-layered glasses engraved with figurative scenes. The most famous work of this kind is the Barberini-Portland vase exposed at the British Museum.