public class Sierpinski
{
    public static ArrayList<Square> carpet(ArrayList<Square> l, int levels)
    {
        // TODO: Milestone 2
        if(levels < 0)
            throw new IllegalArgumentException();

        // TODO: Milestone 3
        if(levels == 0)
            return l;

        // TODO: Milestone 4
        ArrayList<Square> newSquares = new ArrayList<>();



        for(Square x: l)
        {
           Square newSquare1 = new Square();
           Square newSquare2 = new Square();
           Square newSquare3 = new Square();
           Square newSquare4 = new Square();
           Square newSquare5 = new Square();
           Square newSquare6 = new Square();
           Square newSquare7 = new Square();
           Square newSquare8 = new Square();

           if(levels > 0)
           {
               int newH = x.getHeight() / 3;
               int newW = x.getWidth() / 3;

               newSquare1.setHeight(newH);
               newSquare1.setWidth(newW);
               newSquare2.setHeight(newH);
               newSquare2.setWidth(newW);
               newSquare3.setHeight(newH);
               newSquare3.setWidth(newW);
               newSquare4.setHeight(newH);
               newSquare4.setWidth(newW);
               newSquare5.setHeight(newH);
               newSquare5.setWidth(newW);
               newSquare6.setHeight(newH);
               newSquare6.setWidth(newW);
               newSquare7.setHeight(newH);
               newSquare7.setWidth(newW);
               newSquare8.setHeight(newH);
               newSquare8.setWidth(newW);

               int x1 = x.getX();
               int x2 = x.getX() + newW;
               int x3 = x1 + 2 * newW;

               int y1 = x.getY();
               int y2 = y1 + newH;
               int y3 = y1 + 2 * newH;

               newSquare1.setX(x1);
               newSquare1.setY(y1);
               newSquares.add(newSquare1);

               newSquare2.setX(x2);
               newSquare2.setY(y1);
               newSquares.add(newSquare2);

               newSquare3.setX(x3);
               newSquare3.setY(y1);
               newSquares.add(newSquare3);

               newSquare4.setX(x1);
               newSquare4.setY(y2);
               newSquares.add(newSquare4);

               newSquare5.setX(x3);
               newSquare5.setY(y2);
               newSquares.add(newSquare5);

               newSquare6.setX(x1);
               newSquare6.setY(y3);
               newSquares.add(newSquare6);

               newSquare7.setX(x2);
               newSquare7.setY(y3);
               newSquares.add(newSquare7);

               newSquare8.setX(x3);
               newSquare8.setY(y3);
               newSquares.add(newSquare8);
           }

        }

        return carpet(newSquares, levels - 1);
    }
}