private boolean isEdgeNode(int index)
	{
		int x = index % width;
		int y = index / width;
		boolean isValid = false;
		if( (x == 0 || x == width - 1) && (y > 0 && y < height - 2) )
		{
			isValid = true;
		}
		else if( (y == 0 || y == height - 1) && (x > 0 && x < width - 2) )
		{
			isValid = true;
		}
		else
		{
			isValid = false;
		}
		
		return isValid;
	}