public void createSquareWall() {
		//create horizontal walls (WEST to EAST)
		for (int i = 0; i < sizeY; i++) {
			place(new Wall(0, i));
			place(new Wall(sizeX - 1, i));
			
		}
		
		//create "vertical" walls (NORTH to SOUTH);
		for (int i = 1; i < sizeX - 1; i++) {
			place(new Wall(i, 0));
			place(new Wall(i, sizeY - 1));
			
		}
	}