[Eliji Hayashi's] project for a class at Carnegie Mellon University is absolutely delightful! It is a game he calls Laser Command because a laser pointer is used as the gaming controller. An 8×8 LED matrix serves as the display, but is also used as an 8×8 light sensor, much the same way as the LED advent project did. The display is rapidly switched between producing light and sensing it. The laser is bright enough that it becomes easy to pick up the voltage generated within the matrix during the sensing periods. The game is programmed on an Arduino mini and the whole thing wraps up into an incredibly small package. Brilliant.