We demonstrate a simple technique that allows tangible objects to track their own position on a surface using an off-the-shelf optical mouse sensor. In addition to measuring the (relative) movement of the device, the sensor also allows capturing a low-resolution raw image of the surface. This makes it possible to detect the absolute position of the device via marker patterns at known positions. Knowing the absolute position may either be used to trigger actions or as a known reference point for tracking the device. This demo allows users to explore and evaluate affordances and applications of such tangibles.