import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;

    public class Chess extends Frame {

         public void paint(Graphics g) {
          Graphics2D graph = (Graphics2D)g;

          graph.setStroke(new BasicStroke(3f));
    int cnt = 0;
          for(int x = 100 ; x <=450 ; x+=50) {
             cnt++;
              for(int y = 100 ; y <=450 ; y+=50) {
                  cnt++;
                  Shape square = new Rectangle2D.Double(x, y,50,50);
                  graph.draw(square);
                  if(cnt % 2 == 0)
                      graph.fill(square);
              }
          }
         }


    public static void main(String[] args) {
          Frame frame = new Chess();

          frame.addWindowListener(
                  new WindowAdapter(){
                      public void windowClosing(WindowEvent we){
                      System.exit(0);
                     }
                    }
                  );
          frame.setSize(1000, 1000);
          frame.setVisible(true);


    }

    }