static void Main(string[] args)
{
Car car = new Car("BMW", 5, "V8", 20);
car.Display();
MotorBike bike = new MotorBike("Honda", 3, "1000", 10);
bike.Display();
Rentalable rentableVehicle = new Rentalable(car);
rentableVehicle.RentItem("Johnny");
rentableVehicle.RentItem("Mary");
rentableVehicle.Display();
}