public class WalkablesTest 
{
    public static void main(String[] args) 
    {
        Animal[] aList = new Animal[5];
        aList[0] = new Person("Jack");
        aList[1] = new Fish("Nemo");
        aList[2] = new Duck("Donald");
        aList[3] = new Person("John");
        aList[4] = new Duck("Dagobert");
        
        
        // Let every Animal walk
        Walkables.letAnimalsWalk(aList);
   
    }
}