1
general::
Complex interacting processes, agents, or motives, as in It's difficult to find out just which government agency is responsible; there are wheels within wheels. This term, which now evokes the complex interaction of gears, may derive from a scene in the Bible (Ezekiel 1:16): "Their appearance and their work was as it were a wheel in the middle of a wheel." [c. 1600]
American Heritage Idioms