Piramida u Graphics Programu JAVA

[Badoo]

Ovo je zadatak koji treba da uradim:

Write a GraphicsProgram subclass that draws a pyramid consisting of bricks arranged in horizontal rows, so that the number of bricks in each row decreases by one as you move up the pyramid, as shown in the following sample run:




The pyramid should be centered at the bottom of the window and should use constants for the following parameters:

BRICK_WIDTH The width of each brick (30 pixels)
BRICK_HEIGHT The height of each brick (12 pixels)
BRICKS_IN_BASE The number of bricks in the base (14)

Ovo je moj kod, ono to sam uradio koliko sam mogao:

import acm.program.*;
import acm.graphics.*;

public class Pyramid extends GraphicsProgram {
private static final int BRICK_WIDTH = 30;
private static final int BRICK_HEIGHT = 12;
private static final int BRICKS_IN_BASE = 14;

public void run() {
		
		
		  for (int i = 1; i <= BRICKS_IN_BASE; i++) {
	            for (int j = 0; j < i; j++) {
	                int x = BRICK_WIDTH * j;
	                int y = BRICK_HEIGHT * i;
	        
	                GRect rect = new GRect(x, y, BRICK_WIDTH, BRICK_HEIGHT);
	                add(rect);
	               
	                
	            }
	        }

Ono sto mi nije jasno, ne znam kako da je centriram u Graphics Programu. Nasao sam na Stack-u i odgovor na ovo isto pitanje (pri cemu je moj kod skoro identican, evo i linka: http://stackoverflow.com/questions/7191450/exercise-write-a-graphics-program-that-draws-a-pyramid), ali nisam najbolje razumeo sta je pisac hteo da kaze. Ne razumem kako da napravim odredjenu povrsinu za tu piramidu u kojoj cu je postaviti na sredini i onda da postavim svaki blok kako je receno u zadatku :wall:. Problem su te koordinate odakle da krenem, koordinata po x se smanjuje za BRICK_WIDTH/2, ali ne znam kako to da iskazem kroz kod.
Bilo bi odlicno ako ovo neko znam da uradi ovo ili da mi da neki predlog. Mucim se sa ovim vec nekoliko dana.