The design of each Muppet’s face is based on a secret formula created by Jim Henson. It’s called “the magic triangle” and it refers to the relationship between the eyes and the nose.
The eyes have it: Muppets’ eyes are made of a toy called “Wacky Stacks,” which were popular for a short time in the 1970s. They’re white plastic balls that “nest” inside other, bigger white plastic balls of graduating sizes. Legend says that Jim Henson purchased the entire inventory of Wacky Stacks when the company went under, but no one will either confirm or deny that rumor.
Muppet designers use different sized pupils depending on the desired “age” of the Muppet. The smaller the pupil, the more mature the Muppet looks; the larger the pupil, the younger it looks.
Some of the Muppets’ “ingredients” are far from high-tech or expensive. For example, Sesame Street resident Zoe has a nose made from a plastic grape covered in fleece!
The Inner Workings of a Muppet
Two-handed Muppets, such as Ernie and Cookie Monster, require two Muppeteers. They’re “worn” by the Muppeteer who provides the character’s voice: the Muppet goes over his or her head, with the right hand in the mouth and the left in the Muppet’s left hand. The other Muppeteer controls the right hand, which does the majority of the actions and handles any props.
Rod Muppets, such as Bert, Grover, and Kermit, only require one Muppeteer: his or her right hand goes in the Muppet’s mouth, and the left hand works the rods which are attached to the Muppet’s hands or feet.
Big Bird is a little different. His Muppeteer, Caroll Spinney, is actually inside the costume. He puts his right hand into Big Bird’s head to work the mouth and eyes, and his left hand works Bird’s arms. Bird’s right arm works like a marionette, attached with an invisible wire to a ring in his head. Spinney has a microphone and monitor inside his costume that allows him to see what he’s doing. His view is the same view that the audience sees.
Muppeteers work from the ground, either crouching or sitting or lying down. Normally, they’re propped on a rolling cushion so that can move quickly and smoothly in and out of frame.
Muppeteers don’t look up at the Muppets or at each other, but at a monitor that displays the same scene that the viewers see at home. This way, they can more easily see how well their character is interacting with the others. They don’t have to memorize their lines, because they work from a script that is taped to the monitor.