Recursive Squares java in a pgm

RecursiveSquares.java

public class RecursiveSquares

{

    public static void drawSquare(double x, double y, double size)

   {

        StdDraw.setPenColor(StdDraw.LIGHT_GRAY);

        StdDraw.filledSquare(x, y, size/2);

        StdDraw.setPenColor(StdDraw.BLACK);

        StdDraw.square(x, y, size/2);

    }

    public static void draw(int n, double x, double y, double size)

   {

        if (n == 0) return;

        drawSquare(x, y, size);

                    double ratio = 2.2;

        draw(n-1, x - size/2, y - size/2, size/ratio);   

        draw(n-1, x - size/2, y + size/2, size/ratio);   

        draw(n-1, x + size/2, y - size/2, size/ratio);   

        draw(n-1, x + size/2, y + size/2, size/ratio);   

    }

                public static void main(String[] args)

                {

        int N = Integer.parseInt(args[0]);

        double x = 0.5, y = 0.5;  

        double size = 0.5;        

        draw(N, x, y, size);

    }

            }