Recursive squares

Square.java

public class Square
{
    public static void drawSquare(int N, double x, double y, double r)
    {
	if(N == 0)
	    return;
	StdDraw.square(x, y, r);
	StdDraw.show(100);
	drawSquare(N-1, x - r , y + r, r/2.2);
	drawSquare(N-1, x + r , y + r, r/2.2);
	drawSquare(N-1, x + r , y - r, r/2.2);
	drawSquare(N-1, x - r , y - r, r/2.2);
    }
    public static void main(String[] args)
    {
	int N = Integer.parseInt(args[0]);
	StdDraw.setXscale(-N, N);
	StdDraw.setYscale(-N, N);
	drawSquare(N, 0, 0, N/2);
    }
}