1. A game system, comprising: a first mobile device comprising a microprocessor, a memory and a light generating device, and configured to project a light beam having a first characteristic on an overhead surface; and a second mobile device comprising a microprocessor, a memory and a sensor, and configured to: detect a reflection of the projected light beam having the first characteristic on the overhead surface; determine a direction and a distance of the second mobile device in relation to a position of the first mobile device based on the detected reflection; and generate movement commands for the second mobile device based in part on the determined direction and distance.