Part of the "Megastructures: The Visual Encyclopedia" book project, on sale now at http://www.neilblevins.com/projects/megastructures/megastructures.htm
A Polyhedral Habitat would be a space colony consisting of several O’Neill Cylinders attached together to form a larger structure, much like struts forming a children’s jungle gym. The colony as a whole would not rotate to create spin gravity, but each cylinder would rotate along its axis like a standalone cylinder. The tips of the individual cylinders would be attached to adjoining cylinders by joints called knuckles. The knuckles would not rotate and, because of that, would have no gravity inside.