A trucking firm has a contract with 8 different stores under which it agrees to deliver packages for them within a small urban area. Packages are placed on a loading dock each day at each of the stores, at 8:00 a.m., and again at 1:00 p.m. Each store simultaneously lets the dispatching agent at the trucking firm know how many "new" packages have just been made available for delivery. (Note that, at any particular 8:00 a.m. or 1:00 p.m., there may still be "old" packages on the loading dock, which the trucking firm has not yet gotten around to picking up.) The dispatching agent consequently knows at all times exactly how many packages are waiting for pickup at each of the 8 stores.