1. A computing device comprising: a display device including one or more optical sensors configured to detect images projected onto a surface of the display device by a stylus; an image decoder module configured to: decode a detected image to ascertain a corresponding context for interaction with the computing device using the stylus by recognizing the detected image from multiple different images that each represent different contexts, the multiple different images each corresponding to a graphic that results from illuminating a series of image elements of the stylus differently than the series of image elements is illuminated for other graphics; and cause performance of one or more actions by the computing device that are associated with the ascertained context.