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

public class Tilk4 extends Applet implements Runnable{
   boolean veel=false;
   int ooteaeg=300;
   
   public void start(){
     new Thread(this).start();
   }
   
   public void stop(){
     veel=false;
   }
   
   void uusTilk(){
     new Tilk4Loim((int)(300*Math.random()), 
                   (int)(200*Math.random()),
                   getGraphics()
     ).start();
   }
   
   public void run(){
     veel=true;
     Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
     while(veel){
       uusTilk();
       try{Thread.sleep(ooteaeg);}catch(Exception e){}
     }
   }
   
   static void joonistaTilk(Graphics g, int x, int y){
     g.fillOval(x, y, 10, 10);
     Polygon p=new Polygon();
     p.addPoint(x, y+5);
     p.addPoint(x+10, y+5);
     p.addPoint(x+5, y-10);
     g.fillPolygon(p);
   }
   public static void main(String argumendid[]){
     Frame f=new Frame("Mitu tilka");
     Tilk4 t=new Tilk4();
     f.add(t);
     f.setSize(300, 300);
     f.setVisible(true);
     t.start();
   }
}


class Tilk4Loim extends Thread{
  int x, y;
  Graphics g;
  public Tilk4Loim(int ux, int uy, Graphics ug){
    x=ux; y=uy;
    g=ug;
  }
  public void run(){
     double vahe=0.5;

     for(int d=0; d<10; d+=2){
       g.setColor(Color.blue);
       g.fillOval(x, y, d, d);
      try{
        Thread.sleep(30);
      }catch(Exception ex){}
       g.setColor(Color.white);
       g.fillOval(x, y, d, d);
     }

     for(;y<250; y=(int)(y+vahe), vahe=vahe+0.2){
      g.setColor(Color.blue);
      Tilk4.joonistaTilk(g, x, y);
      try{
        Thread.sleep(30);
      }catch(Exception ex){}
      g.setColor(Color.white);
      Tilk4.joonistaTilk(g, x, y);
     }

     for(int d=10; d>0; d--){
       g.setColor(Color.blue);
       g.fillOval(x, y, d, d);
      try{
        Thread.sleep(30);
      }catch(Exception ex){}
       g.setColor(Color.white);
       g.fillOval(x, y, d, d);
     }
  }
}