Col. Gadhafi cut off phone and internet service a month ago, and that’s made things incredibly difficult for Libyan rebels. On the battlefield, they’d communicate by waving flags: green for advance, yellow for retreat. But a Libyan-American telcom executive helped hijack Col. Gadhafi’s Tripoli-based Libyan General Telecommunications Authority to create a new network that can’t be monitored by the government. It’s been up since April 2, and is now the main way the rebels communicate with each other. The Wall Street Journal has the story of how this network got from an idea written on the back of a napkin to a full-fledged operating network.