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

public class Loim2 extends Applet implements Runnable{
 Pall2[] pallid;
 Image pilt;
 public Loim2(){
   pallid=new Pall2[5];
   for(int i=0; i<pallid.length; i++)
     pallid[i]=new Pall2();
   new Thread(this).start();
 }
 public void joonista(){
  if(pilt==null) pilt=createImage(200, 200);
  if(pilt!=null){
   Graphics piltg=pilt.getGraphics();
   piltg.setColor(Color.white);
   piltg.fillRect(0, 0, 200, 200);
   piltg.setColor(Color.black);
   for(int i=0; i<pallid.length; i++){
     piltg.drawOval(pallid[i].x()-10, pallid[i].y()-10, 20, 20);
   }
   this.getGraphics().drawImage(pilt, 0, 0, this);
  }
 }
 public void run(){
   while(true){
     joonista();
     Thread.yield();
     try{Thread.sleep(50);}catch(Exception e){}
   }
 }
 public static void main(String argumendid[]){
   Frame f=new Frame("Pallikesed");
   f.add(new Loim2());
   f.setSize(220, 220);
   f.setVisible(true);
 }
}

class Pall2 extends Thread{
  double x=100, y=100, dx, dy;
  int vasak=20, ulal=50, parem=180, all=180;
  public Pall2(){
    dx=5*Math.random();
    dy=5*Math.random();
    start();
  }
  public int x(){
    return (int)x;
  }
  public int y(){
    return (int)y;
  }
  public void run(){
    setPriority(Thread.NORM_PRIORITY-2);
    while(true){
      if(x>parem)dx=-Math.abs(dx);
      if(y>all)dy=-Math.abs(dy);
      if(x<vasak)dx=Math.abs(dx);
      if(y<ulal)dy=Math.abs(dy);
      x+=dx;
      y+=dy;
      yield();
      try{Thread.sleep(50);}catch(Exception e){}
    }
  }
}