When 2 people of similar ranks and/or tenure are working together closely on the same projects and they each keep managing to delegate tasks back and forth more than once each.
Eric walks into Bill's office and states "Bill, I need you to work up a proposal for the Cincinnati project." Bill says, "OK, can you review this report and print it in color?" As Eric lays 2 folders on Bill's desk, he says, "Sure. And by the way, here is the information you need to finish the Oklahoma project." Bill says, "thank you." and as Eric is leaving Bill's office, Bill zips Eric an email requesting Eric to fill-in for him at this week's seminar. Thus, a delegation duel.