James Maury "Jim" Henson was one of the most important puppeteers in modern American television history. He was also a filmmaker and a television producer, but is most famous for creating the puppet group the Muppets, and was the leading force behind their long, creative run on the television shows Sesame Street and The Muppet Show, as well as in subsequent films. Henson created the prototype for his signature character, Kermit the Frog, from what discarded materials?