duck = quack = prn "Quack" fly = prn "Flap, Flap" person %n = quack = prn "@%n walks in the forest and imitates ducks to draw them" fly = prn "@%n takes an airplane" quack-and-fly %x = %x quack; %x fly quack-and-fly: duck quack-and-fly: person "Jules Verne"