Experiences with the alternate reality kit: an example of the tension between literalism and magic

This paper presents an overview of the Alternate Reality Kit (ARK), an animated environment for creating interactive simulations. ARK is built upon a physical-world metaphor: all objects have an image, a position, a velocity, and can experience forces. Users manipulate objects with a mouse-operated “hand” which enables them to carry and throw objects, to press buttons, and to operate sliders.The interface features are discussed in light of a general user interface tension between literalism and magic. Literal features are defined to be those that are true to the interface's metaphor. Literal features enhance an interface's learnability. Magical features are defined to be those capabilities that deliberately violate the metaphor in order to provide enhanced functionality. Discussion of each ARK feature includes informal observations of early ARK users, an assessment of the feature's learnability, of its usefulness, and of its position on the magical-literal axis.Even though ARK includes magical features, applications-level users have be trained in a few minutes. Although this paper is about ARK, the tension between literalism and magic raises some interesting questions on its own. Some of these questions are presented briefly in the conclusion.