place the puppeteer's hand in just the puppet's head, controlling the mouth and head, and the puppet's body then hangs over the entire arm. Other parts of the puppet (mainly arms) are usually not much larger than the hand itself. Often the mouth can also open and close, and special variants exist with eyelids that can be manipulated. A sock puppet is a particularly simple type of hand puppet made from a sock. Human-arm puppet Also called a "two-man puppet" or a "live-hand puppet", the human-arm puppet is similar to a hand puppet but is larger and requires two puppeteers. One puppeteer places their dominant hand inside the puppet's head and operates the puppet's head and mouth, while putting their non-dominant arm into a glove and special sleeve attached to the puppet. The second puppeteer puts their arm into a glove and special sleeve attached to the puppet in order to operate the other arm. This way, the puppet can perform hand gestures. This is a form of glove or hand puppetry and rod puppetry. Some of Jim Henson's Muppets, such as the Muppet character Fozzie Bear and the Sesame Street characters Ernie and Count von Count, are live-hand puppets, as are Yoda and ALF. A variation of this puppet, called a "sack-body" puppet, is built with the puppet's arms directly connected to its base. Popular examples include the Sesame Street characters Cookie Monster and Oscar the Grouch, and the Muppet character Rowlf the Dog. The Swedish Chef, another Muppet character, is operated in a unique way; both of his hands are actual human hands, supplied by the second performer. The technique of the main puppeteer performing a character's head with an assistant performing both arms is also used for Rowlf playing the piano. Light curtain puppet Light curtain puppet presentations use light to highlight small portions of a performance area, allowing the puppet to be seen while the manipulators remain invisible. The puppets stand on a stage divided into an unlit background and a well-lit foreground, meeting to form a "curtain" of light. The puppeteer dresses in black and remains hidden in the unlit background of the stage while the puppet is held across the light curtain in the lit foreground of the stage. "Light curtain puppet" is an umbrella term, and any puppet which is extended into a well-lit area where its handler remains separated from the puppet