In a few years, an iPhone app may give you a 3D layout of a room as soon as you step into it. Researchers have developed an algorithm that spits out the shape and contours of complex structures (including Switzerland's Lausanne Cathedral) using data compiled from four randomly placed microphones. The technology, which relies on the same sort of echolocation bats and dolphins use to navigate, could be used to develop more realistic echoes in video games and virtual reality simulations and to eliminate the echo from phone calls."