如何实现用java实现下图所示的图形，急用~~~~

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Polygon;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class DrawDemo extends JPanel {

public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;

// 画大矩形
g2d.drawRect(10, 15, 200, 200);
// 小矩形
g2d.drawRect(15, 20, 90, 60);
g2d.drawRect(20, 30, 50, 40);

Polygon p = new Polygon();
p.addPoint(80,40);
p.addPoint(80,60);
p.addPoint(100,50);
g2d.drawPolygon(p);
}

public static void main(String[] args) {
DrawDemo rects = new DrawDemo();
JFrame frame = new JFrame("画图");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(rects);
frame.setSize(500, 400);
frame.