Eyes. This section explains the moving eye assembly.
The assembly is mounted on a platform that slides into the back of Fred's head and rests on the small shelves on either inside wall. Page 132 in Figure Making Can Be Fun has a lot of detail about eyes and eye mechanisms. You can build eyeballs as described here or you can purchase the Pro Vent Figure Eyeballs. These eyeballs come complete with irises. PuppetryLab.com. Puppetools - Advancing the science of play in education.