public class MouthKiss 
{
    public static void main (String[] args)
    {
        ArrayList<Shape> shapes = new ArrayList<Shape>();
        shapes.add(new Square(10));
        shapes.add(new Rectangle(5, 5));
        shapes.add(new Triangle(30, 2));
        
        for (Shape s: shapes)
        {
            System.out.println("Area of this object: " + s.getArea());
        }
    }
}