For Loop drawPolygon

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)

/**
 * Write a description of class MyWorld here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Background extends World
{

    /**
     * Constructor for objects of class MyWorld.
     * 
     */
    public Background()
    {    
        // Create a new world with 600x400 cells with a cell size of 1x1 pixels.
        super(600, 600, 1);
        setBackground(Background());
    }
    
    public GreenfootImage Background()
    {
        GreenfootImage background = new GreenfootImage(getWidth(), getHeight());
        background.setColor(Color.BLACK);
        
        for (int i = 0; i < 9; i++)
        {           
            int [] x = {getWidth()/2, getWidth(), getWidth()*0};
            int [] y = {getHeight()*0, 150+getHeight()/2, 150+getHeight()/2};
            background.drawPolygon(x, y, 3);
            background.rotate(180);
        }
        
        return background;       
    }
}