a descriptive phrase used to indicate that a situation is complex, requires attention in multiple areas simultaneously, or has several interdependencies; can evoke an intricate piece of machinery or, for those situations that have arisen more haphazardly, a Rube Goldberg-esque contraption, as in: “I’ve been swamped trying to manage this project, it has so many moving parts”; similar to have a lot of balls in the air, which is employed when juggling is the preferred metaphor; related to black box, which refers to something of such complexity that at best it can be imperfectly understood