WiFi signals can turn your room into a co-processor

We're not sure if there are any practical applications, but apparently researchers toyed with WiFi routers and figured out a method to use WiFi signals to turn your house into a co-processor. The feat is achieved by measuring and controlling reflections of WiFi radio waves. A detailed explanation can be read at ARS Technica, it's neat but probably largely pointless.

When two waves overlap, we measure the combination of the two: the amplitude of one wave is added to the amplitude of the other. Depending on the history of the two waves, one may have a negative amplitude, while the other may have a positive amplitude, allowing for simple computation. The idea here is to control the path that each wave takes so that, when they're added together, they perform the exact computation that we want them to.