Graphics paint component and loop trouble

Question

I can not seem to figure out why my concentric circles are not lining up. My loops seem correct to me and the measurements are correct but for some reason the last few circles are off-centered. That's the first issue I'm having. The second issue is, i can't seem to get the concentric circles to print in each square. Once again, i can't seem to find any issue in my logic, but obviously there is an issue. Any help on this at all would be great.

This should be the end product

*Now this is my source code- ExampleGUI.java *

import javax.swing.*;

public class ExampleGUI {
public static void main(String args []) {


    JFrame frame = new JFrame("Example Graphics");
    ExamplePanel panel = new ExamplePanel();

    frame.getContentPane().add(panel);
    frame.setDefaultCloseOperation(3);
    frame.pack();
    frame.setVisible(true);

}
}

* ExamplePanel.java *

import java.awt.*;

import javax.swing.*;



public class ExamplePanel extends JPanel{

public ExamplePanel() {
    setPreferredSize(new Dimension (600, 600));
}

public void paintComponent(Graphics g) {
    super.paintComponent(g);


    int x = 0;
    int x2 = 5;
    int y = 500;
    int y2 = 505;
    int w = 100;
    int w2 = 90;
    int h = 100;
    int h2 = 90;
    int i, j, k;

    for(j = 1; j < 7; j++) {
        x = 0;
        x2 = x + 5;

        for(i = 1; i < 7; i++) {
            if ((i + j) % 2 == 0) {
                g.setColor(Color.white);
            }  else {
                g.setColor(Color.yellow);
            }
            g.fillRect(x, y, w, h);
            g.setColor(Color.black);
            g.drawRect(x, y, w, h);
            g.setColor(Color.green);
            g.fillOval(x2, y2, w2, h2);

                for(k = 1; k < 7; k++) {
                    g.setColor(Color.black);
                    g.drawOval(x2, y2, w2, h2);
                    x2 = x2 + 5;
                    y2 = y2 + 5;
                    w2 = w2 - 10;
                    h2 = h2 - 10;
                }
            x = x + w;
            x2 = x2 + w2 + 10;

        }


        x = x + w;

        y = y - h;
        y2 = (y2 - h2) - 10;
    }

}
}

* This is what my program looks like when i run it. It doesn't look like the other picture for some reason *

Answer 1

Basically, you "spiral" loop is modifying the state of variables that are required elsewhere

What I would do, is create a new series of variables, initialized to the current state and modify those instead...

                int ix = x2;
                int iy = y2;
                int ih = h2;
                int iw = w2;
                for (k = 1; k < 7; k++) {
                    g.setColor(Color.black);
                    g.drawOval(ix, iy, iw, ih);
                    ix = ix + 5;
                    iy = iy + 5;
                    iw = iw - 10;
                    ih = ih - 10;
                }