Wearable Multitouch Interaction is a depth-sensing and projection system that enables interactive multitouch applications on everyday surfaces. Beyond a shoulder-worn system, there is no instrumentation of the user or the environment. Foremost, on such surfaces—without calibration—Wearable Multitouch Interaction provides capabilities similar to those of a mouse or a touchscreen: X and Y locations in 2-D interfaces and whether fingers are “clicked” or hovering, enabling a wide variety of interactions. Reliable operation on the hands, for example, requires buttons to be 2.3 centimeters in diameter. Thus, it is now conceivable that anything one can do on today’s mobile devices can be done in the palm of a hand.