如何画一个方形螺旋？

请告诉我如何画一个方形螺旋？一开始我试着用线条来画，但不太成功，也许是这个图的公式？目前我在正方形的帮助下绘制，但结果不是我需要的。

import javax.swing.*;
import java.awt.*;
import java.awt.geom.Line2D;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class Spiral {
    private static JFrame frame;
    private static int x, x2;
    private static int y, y2;
    private static int x1;
    private static int y1;
    private static int n;
    private static int step;
    private static Line2D.Double line = null;

    public Spiral(){
        x = 300;
        y = 200;
        x2 = 400;
        y2 = 200;
        step = 30;
    }
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Enter number: ");
        n = Integer.parseInt(reader.readLine()) ;

        frame = new JFrame("Spiral");
        frame.setSize(600,400);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        GraphicsComponent gc = new GraphicsComponent();
        frame.add(gc);
        frame.setVisible(true);
    }

    static class GraphicsComponent extends JComponent {
        @Override
        protected void paintComponent(Graphics g) {
            Graphics2D g2 = (Graphics2D) g;
            x1 = 250;
            y1 = 50;

            int size = n * n;
            for (int i = 0; i < n; i++) {
                Rectangle rectangle = new Rectangle(x1, y1, size, size);
                size -= 10;
                x1 += 5;
                y1 += 5;
                g2.draw(rectangle);
            }

            /*
            int dir = 0;
            for (int i = 1; i <= 6; i++) {
                if (dir == 0){
                    line = new Line2D.Double(x, y, x2 ,y2);
                    drawLine(g2);
                    dir++;
                }
                else if(dir == 1){
                    x = x2;
                    y = y;
                    x2 = x2;
                    y2 += STEP;
                    line = new Line2D.Double(x, y, x2 ,y2);
                    drawLine(g2);
                    dir++;
                }
                else if(dir == 2){
                    x = y2 + STEP;
                    y = y2;
                    x2 -= 0;
                    y2 = y2;
                    line = new Line2D.Double(x, y, x2 ,y2);
                    drawLine(g2);
                    dir++;
                }
                else if(dir == 3){
                    x = x;
                    y = y;
                    x2 = x;
                    y2 -= STEP;
                    line = new Line2D.Double(x, y, x2 ,y2);
                    drawLine(g2);
                    dir++;
                }
                else if(dir == 4){
                    x = x;
                    y = y;
                    x2 = x;
                    y2 -= STEP;
                    line = new Line2D.Double(x, y, x2 ,y2);
                    drawLine(g2);
                    dir++;
                }
                else if(dir == 5){
                    x = x;
                    y = y2;
                    x2 += STEP;
                    y2 = y;
                    line = new Line2D.Double(x, y, x2 ,y2);
                    drawLine(g2);
                    dir = 1;
                }
            }
            */
        }
    }

    private static void drawLine(Graphics2D g2){
        g2.setColor(Color.RED);
        g2.fill(line);
        g2.draw(line);
    }
}