This video shows the technique of making a kuttrolf, an object in the exhibition Medieval Glass for Popes, Princes, and Peasants, on view at The Corning Museum of Glass from May 15, 2010 to January 2, 2011.
(German) A flask with the neck divided into two or more tubes. The Kuttrolf, which has Roman antecedents, was produced by German glassworkers in the later Middle Ages; it is also found among Venetian and façon de Venise glasses of the 16th and 17th centuries.