import java.applet.Applet;
    import java.awt.Color;
    import java.awt.Dimension;
    import java.awt.Graphics;
    import java.util.ArrayList;

    public class Appl extends Applet implements Runnable{
            ArrayList<Kwadrat> lista;

            public int losuj(int a, int b){
                    return a+(int)(Math.random() * (b-a));
            }

            public Appl(){
            }

            @Override
            public void init() {
                 int N = 3;
                 String ile = null;
                 ile = getParameter("ILE_KWADRATOW");
                 if(ile != null){
                    try{
                        N=Integer.parseInt(ile);
                    }catch(NumberFormatException e){
                        System.err.println("Błedna wartość " + ile );
                     }
                 }

                 lista = new ArrayList<Kwadrat>(N);
                 Dimension d = getSize();
                 for (int i = 0; i < N; i++){
                         lista.add(new Kwadrat(losuj(20,60),d));

                 }

                 setBackground(Color.blue);
                 new Thread(this).start();
            }

            public void paint(Graphics g){
                    for(Kwadrat k : lista)
                            k.rysuj(g);

            }
            public void run(){
                    while(true){
                            try{
                                    Thread.sleep(300);
                            }catch(InterruptedException e){

                            }
                            for(Kwadrat k : lista)
                                    k.zmniejsz();
                            repaint();
                    }
            }


    }