elementary OS began life over a decade ago as a set of icons. (Yes, seriously.) If ever there was a group of developers who started at the bottom and worked their way up to the top, it's Daniel Foré and the rest of today's elementary OS team. From a set of icons designed to improve the look of Ubuntu's then GNOME 2 desktop, the elementary project expanded to include some custom apps, including a fork of the default GNOME files app, Nautilus, called nautilus-elementary. As with most open source projects, the borrowing went both ways: Ubuntu's Humanity theme was a fork of elementary OS's icon set.