This is Roald Tweet on Rock Island. Within ten miles of Rock Island, four hundred and ninety-three restaurants lie in wait, menus at attention. Four hundred and seventy-nine of these serve pizza, spaghetti, salmon in dill sauce, hot beef sandwiches, Iowa pork chops, pancakes, along with potatoes that are hashed, mashed, baked, creamed, or French, cottage, or home fried. Customers sit, order, eat, tip and leave.