System Overview

As mentioned before, the DataTiles project could be qualified as a physical framework. This makes it difficult to describe the possibilities of the system within a few lines. As a consequence, this section gives an overview of the architecture, focusing on the capabilities of some existing tiles.
At a basic level the system integrates three interaction concepts:

1. Tagged objects (tiles) as graspable module to represent digital media and to trigger specific actions.
   This is the relational part of the TUI.
2. Mixed visual and physical interactions.
3. Physical combinations of tokens to create complex behaviors and actions.
   This is the constructive part of the interface.

To enable these interactions five categories of tiles are proposed:

1. Application Tiles have predefined behaviors. When such a tile is disposed on the tray, the system starts the corresponding application and displays it through the token. These tiles are basically graspable representations of digital information or media. The wheather forecast server or the scribble tool are example of such tiles.
2. Portal Tiles represent physical objects or places as well as digital entities. A printer or a webcam are two examples of portal tiles.
3. Parameter Tiles are used to manipulate and control other tiles. For instance one could use a ``wheel'' tile⁸ to control the time point of an application tile displaying a movie.
4. Container Tiles are used to store data extracted from other tiles. Such a token can then be transported on another tray or to any appliance supporting tiles. This concept is similar the ``blocks'' developed by Ullmer, Ishii and Glas (see 2.1.).
5. Remote Tiles are used to connect different trays. When such a tile $t_{0}$ is placed next to another, $t_{1}$ the content of $t_{1}$ is continuously sent by $t_{0}$ to a twin of $t_{1}$, $t_{1remote}$, on a remote tray.

Moreover, to better understand the way tiles can be used for complex interaction a use-case example is of great value.
To begin with one can drag a Weather tile (application tile) and place in on the tray. It is worth noting that the tile may be transparent or may have some patterns printed on it. Indeed, remember the tiles are a mixture of digital and physical information. The Weather tile for instance has a map of the location printed on it. When the system (through the RFID sensor) recognizes the tile it displays the temperatures of the corresponding area through the partially transparent tile.
We now drag a Webcam tile $t_{web}$ (portal tile) and dispose it on the tray. The system recognizes it and displays the corresponding (live) webcam through it. We also place a container tile $t_{cont}$ next to the webcam tile. Using the electromagnetic pen we can now copy (by making a special gesture) the image currently displayed by $t_{web}$ to $t_{cont}$. As a result the system displays a static image of $t_{web}$ through $t_{cont}$.
Again by making a special gesture, one can now use $t_{cont}$ to paste the image onto another tile of the local tray or of a remote tray.
Far more complex interactions and use-cases are enabled by the DataTile system, however these two samples already provide an overview.