Tangible User Interfaces

Back in 1991, Mark Weiser¹ argued that the new generation of computers would enable the users to focus on the task itself rather than on the way of commanding a computer to achieve it [20]. Furthermore, Weiser talked about an abundance of task-specific devices enabling this new way of thinking. Since then, these affirmations are the motto of many researchers towards computer systems that will better fit our needs, our ways of thinking, acting and reacting.
In essence, the Tangible User Interfaces (TUIs) offer a new kind of user experience by introducing physical objects as interfaces for digital manipulations. One can imagine them as being physical extends of the well known GUIs (Graphical User Interfaces).
According to [17] and [3] the properties of tangible objects enable a broad variety of manipulations which are not possible using graphical objects only. First of all using physical objects as interfaces brings to the digital world the degrees of freedom available in the physical world [3]. Additionally, people may use sophisticated skills for manipulating objects [17], leading to an unlimited amount of possible uses and movements. To traditional ``pointing and clicking'' are added rotating, grasping, attaching, dropping, padding, etc.
Moreover, tangible user interfaces enable people to interact cooperatively and act collectively. This latter fact appears quite often in the TUI related literature and is the essence of [3].
Basically tangible objects can serve as interfaces for any kind of action in the digital world. However, this article focuses on the their use for manipulating media. Thus, before going any further it is certainly worth finding an appropriate definition for the term ``media'' in this context.