It's been several days since Australian vessel Ocean Shield detected 'pings' consistent with those from aircraft black boxes, like those on MH370. Unfortunately, the black boxes' battery life might've expired, and they reportedly need to narrow down the location of the signals before they can send an unmanned submersible to scour the ocean floor. A diagram by the Washington Post shows just how challenging pinpointing that location is. Here's an excerpt of it below.

Visit the original source and full text: Shanghaiist