import java.awt.*;  
import java.applet.Applet;

public class Shapes extends Applet {

    public void paint(Graphics g) {
        Circle circle = new Circle(20, 20);
        Square square = new Square(80, 80);

        Shape shape;

        shape = circle;
        shape.draw(g);

        shape = square;
        shape.draw(g);
    }
}

abstract class Shape {

    int x, y;
    int size = 20;

    abstract void draw(Graphics g);

}

class Circle extends Shape {

    Circle(int initialX, int initialY) {
        x = initialX;
        y = initialY;
    }

    public void draw(Graphics g) {
        g.fillOval(x, y, size, size);
    }
}

class Square extends Shape {

    Square(int initialX, int initialY) {
        x = initialX;
        y = initialY;
    }

    public void draw(Graphics g) {
        g.fillRect(x, y, size, size);
    }
}