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 [ quack %q fly %f ] = %q; %f

  quack-and-fly duck
  quack-and-fly person "Jules Verne"