The incalmo technique was developed by Venetian master glassblowers approximately 500 years ago and has traditionally been used to create horizontal bands of color in blown glass. It involves making "cups" of colored glass which are connected together. Steps 1 through 5 of the sketch illustrate the process of making and assembling the cups. The artist then gathers more glass and forms the piece into the desired shape. Incalmo is a technically complex and physically demanding technique to use. An artist must be a proficient glass blower and dedicated to the process in order to master it.