java swing problem z rysowaniem snake

witam, kiedyś kilka wątków wcześniej zacząłem pisać snake w javie. mam problem z rysowaniem węża. stworzyłem okno i tło i na tym etapie się wszystko ładnie wyświetla. mam problem z rysowaniem węża, może ktoś wskazać błąd?? kod wrzucę na githuba jak tylko program ściągnę do obsługi. pozdrawiam i z góry dziękuję za pomoc.

 /*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package javaswingsnake;

import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author marcin
 */
public class JavaSwingSnake {

    /**
     * @param args the command line arguments
     */
    static int timeSpeed = 3000;// 3000ms

    public static void main(String[] args) {
        SnakeWindow snakeWindow = new SnakeWindow();
        while (true) {
            try {
                snakeWindow.repaint();
                Thread.sleep(timeSpeed);
            } catch (InterruptedException ex) {
                Logger.getLogger(JavaSwingSnake.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }
}
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package javaswingsnake;

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.image.BufferStrategy;
import javax.swing.JFrame;

/**
 *
 * @author marcin
 */
public class SnakeWindow extends JFrame {

    static int widthWindow = 800;
    static int heightWindow = 600;
    static int xWindowPosition = 300;
    static int yWindowPosition = 50;
    static int transX;
    static int transY;
    private BufferStrategy bufferStrategy;
    private SnakeWindowBackground snakeWindowBackground;
    private Snake snake = new Snake();

    SnakeWindow() {
        makeScreen();
    }

    private void makeScreen() {
        setTitle("snake");
        setVisible(true);
        setResizable(false);
        setLocation(xWindowPosition, yWindowPosition);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        createBufferStrategy(2);
        bufferStrategy = getBufferStrategy();

        Insets i = getInsets();
        transX = i.left;
        transY = i.top;
       
        setSize(new Dimension(widthWindow + transX + i.right, heightWindow));

        snakeWindowBackground = new SnakeWindowBackground();
    }

    @Override
    public void repaint() {
        Graphics graphics = bufferStrategy.getDrawGraphics();
        draw(graphics);
        graphics.dispose();
        bufferStrategy.show();
    }

    private void draw(Graphics graphics) {
        snakeWindowBackground.draw(graphics);
        snake.draw(graphics);
    }
}
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package javaswingsnake;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;

/**
 *
 * @author marcin
 */
public class SnakeWindowBackground {

    private BufferedImage background;
    static int tileWidth = 10;
    static int tileHeight = 10;

    SnakeWindowBackground() {
        background = new BufferedImage(SnakeWindow.widthWindow, SnakeWindow.heightWindow,
                BufferedImage.TYPE_INT_RGB);
        Graphics graphics = background.getGraphics();

        for (int x = 0; x < SnakeWindow.widthWindow / tileWidth; ++x) {
            for (int y = 0; y < SnakeWindow.heightWindow / tileHeight; ++y) {
                graphics.setColor(Color.gray);
                graphics.drawRect(x * tileWidth, y * tileHeight, tileWidth, 
                        tileHeight);
            }
        }
    }
    
        public void draw(Graphics graphics) {
        graphics.drawImage(background, SnakeWindow.transX, SnakeWindow.transY, null);
    }
        
}

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package javaswingsnake;

import java.awt.Color;
import java.awt.Graphics;
import java.util.Stack;

/**
 *
 * @author marcin
 */
public class Snake {
   
    Stack<SnakePart> snakeParts = new Stack<SnakePart>();

    public Snake() {
        snakeParts.add(new SnakePart(10, 10));
    }
   
    public void draw(Graphics graphics){
        for(int i = 0; i < snakeParts.size(); ++i){
            snakeParts.get(i).render(graphics);
        }
    }
   
}
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package javaswingsnake;

import java.awt.Color;
import java.awt.Graphics;

/**
 *
 * @author marcin
 */
public class SnakePart {
   
    private int xPositionHead;
    private int yPositionHead;
    private int widthTail = 10;
    private int heightTail = 10;

    public SnakePart(int xPositionHead, int yPositionHead) {
        this.xPositionHead = xPositionHead;
        this.yPositionHead = yPositionHead;
    }
   
    public void render(Graphics graphics){
        graphics.setColor(Color.red);
        graphics.fillRoundRect(xPositionHead, yPositionHead, widthTail,
                heightTail, 360, 360);
    }
   
}

Do rysowania służy JPanel, Canvas. Ty rysujesz nie wiadomo gdzie. Intrygujące jest to, że widać siatkę, a nie to, że nie widać węża.
Przy okazji, pomysł by dla narysowania siatki rysować 60*80 = 4800 prostokątów zamiast 61+81 = 142 linii poziomych i pionowych jest dość osobliwy.

Ja radziłbym odejść od pisania gier w Swingu bo istnieją biblioteki do pisania gier w Javie.
Proszę:
http://www.java-gaming.org/index.php?PHPSESSID=mb6f8hns09kiblu6178b449n53&action=resources