This paper describes techniques that allow users to collaborate on tablet computers that employ distributed sensing techniques to establish a privileged connection between devices. Each tablet is augmented with a two-axis linear accelerometer (tilt sensor), touch sensor, proximity sensor, and light sensor. The system recognizes when users bump two tablets together by looking for spikes in each tablet’s accelerometer data that are synchronized in time. Bumping establishes a privileged connection between the devices; the tilt sensing axis (left-right or forward-back) and direction of the spikes determines which sides of the tablets have collided. In previous work, tablets were dynamically tiled together to make a temporary larger display. In this work, users can face one another and bump the tops of two tablets together to establish a collaborative face-to-face workspace. The system then uses the sensors to enhance transitions between personal work and shared work. For example, a user...