[Africa In Fact] In a small, tidy office on the top floor of the Ethiopian Commodity Exchange building in Addis Ababa, communications manager Tewodros Assefa draws two diagrams on a large glass window pane. The window overlooks the capital city's new light rail line, a raised concrete snake that bisects the city. This scene is unexpectedly sophisticated: a modern, first world pastiche in a country better known, not always fairly, for poverty and chaos. Like the new metro, the Ethiopian Commodity Exchange--better known as E