The article focuses on the need of artificial intelligence (AI) in demonstrational computer interfaces. For the past 15 years, about a dozen different applications in many domains in which the user defines behaviors by demonstration have been built. In some of them, the system uses sophisticated AI algorithms, so complex behavior can be inferred from a few examples. In others, the user has to provide the full specification and examples are used primarily to help the user understand the programming situation. Demonstrational interfaces allow the user to perform actions on concrete example objects, often using direct manipulation, though these examples represent a more general class of objects. These actions allow the user to create parameterized procedures and objects without being required to learn a programming language. Demonstrational systems vary greatly along many dimensions. Some of these systems use inferencing, whereby the system employs heuristics to guess the generalization from examples