public void CreateBalls()
    {
        int [] num = new int [4];
        int Ball1 = 0;
        num [0] = Greenfoot.getRandomNumber(5-10); 
        num [1] = Greenfoot.getRandomNumber(5-10);
        num [2] = Greenfoot.getRandomNumber(5-10);
        num [3] = Greenfoot.getRandomNumber(5-10);

        for (int i= 0; i<num.length;i++) 
        {
            num[i] = Ball1;
            getWorld().addObject(Ball1, 300, 200);
        }