Figure 2. (a) PICO (b) Topobo.

a

can be used to engage and communicate. Here, we continue to explore how such motion constructs can be applied for designing user interfaces, in other words, if we imagine that the entire world around us can deform itself in response to our actions, then what kind of user interface experiences and new productivity tools could become possible?

Agrowing number of projects in interface design have laid the groundwork for discussion of kinetic design. Some of the important early exploration has been conducted in the field of Tangible User Interfaces (TUI) [ 4] and ambient user interfaces projects such as Pinwheels and Ambient Fixtures [ 1]. Within tangible interfaces, however, the coupling between the physical and the digital has usually been in one direction only: we can change vital information through physical handles, but the digital world has no effect on physical elements of an interface. Adding elements of kinetic design establishes bi-directional relationships in TUIs significantly expanding their design and interaction vocabulary.

The kinetic interfaces concept, however, is broader

than the TUI paradigm: our inspiration partially comes from one of the earliest visions of computer-controlled kinetic environments suggested by Ivan Sutherland, a pioneer of interactive 3D computer graphics and virtual reality. In 1965 he speculated that the ideal, Ultimate Display would be “ … a room within which the computer can control the existence of matter. A chair displayed in such room would be good enough to sit in. Handcuffs displayed in such a room would be confining, and a bullet … would be fatal” [ 12]. Although manipulating matter on the molecular level, which would be required for such an Ultimate Display, is currently impossible, the Ultimate Display proposes a way of thinking about KOIs as a new category of display devices that communicate information through physical shape and motion. In a sense, every instance of kinetic design discussed here can be considered an early and crude approximation of the Ultimate Display applied to a specific application.

Basic Phrases of Motion. In KOIs, motion can be delineated with physical components that are actuated in a way that can be detected by and respond to the user. There are millions of kinds of motion; however, most of the motions in KOIs can be represented by describing spatial motion of individual elements of the kinetic interface. These motions can be perceived not only visu-