In a Wizard of Oz prototype, you fake most of the functionality of a product or service in the backend while creating a frontend that appears “real” to the person you are testing with. For example, if you are playing around with the idea of adding gesture control to a TV, you don’t need to build a functioning device during your early prototyping phase. Simply sit a person in front of a “regular” TV with a visible “fake” sensor and tell them that this is a gesture-controlled TV. You can teach them a few useful gestures and then tell them that they are free to interact with the TV. What this person doesn’t know is that someone on your team is watching them carefully with the regular TV remote in their hand. This person is called the wizard. It is the wizard’s job to “translate” the observed gestures into regular commands on the TV remote. Carefully, observe the user and find out how they would respond to this gesture-controlled way of interacting with TV. Take note of where they struggle with coming up with the proper gesture for something they want to do. See if they grow tired of using gestures instead of the remote. This kind of feedback is invaluable for you, especially during the early stages of your development process.