namespace Ch1Duck;

public interface IFlyBehaviour {
    void Fly();
}

public class FlyWithWings: IFlyBehaviour {
    public void Fly() {
        Console.WriteLine("I'm flying!");
    }
}

public class FlyNoWay: IFlyBehaviour {
    public void Fly() {
        Console.WriteLine("I can't fly");
    }
}