University of Pennsylvania have flipped the switch on a new type of computer circuit. Unlike conventional silicon, the new chip uses light -- not electricity -- to perform its logic. By creating an array of nano-rods, light-flow can be treated like voltage and current. These rods can then be configured to emulate electrical components such as resistors, inductors and capacitors. The benefits of the so-called "metatronic" system would be smaller, faster and more efficient computer chips, which is clearly a welcome prospect. Another curious property the team discovered, is what it calls "stereo-circuitry." Effectively one set of nano-rods can act as two different circuits, depending on the plane of the field. This means your CPU could become a GPU just by changing the signal. We can't speak for the light itself, but our minds are certainly bent.