The process of forming the upper half of a beaker like the Palmer Cup, using only jacks (shown in Figures 17–21), begins with forming the lower half of the vessel, attaching it to a pontil, and removing it from the blowpipe. Photos for Figures 17–29 are from William Gudenrath, “Glassblowing in the Middle Ages: Tradition and Innovation,” in David Whitehouse, with contributions by William Gudenrath and Karl Hans Wedepohl, Medieval Glass for Popes, Princes, and Peasants, Corning: The Corning Museum of Glass, 2010, pp. 78–82, figs. 6–18.