public Tile getTileByIntExp(int t_i) {
		if (t_i < 0) return null;
		else if (t_i < 4) return _t.get(new BoardCoordinate(3 + t_i, t_i, -3));
		else if (t_i < 9) return _t.get(new BoardCoordinate(t_i - 2, t_i - 4, -2));
		else if (t_i < 15) return _t.get(new BoardCoordinate(t_i - 8, t_i - 9, -1));
		else if (t_i < 22) return _t.get(new BoardCoordinate(t_i - 15, t_i - 15, 0));
		else if (t_i < 28) return _t.get(new BoardCoordinate(t_i - 22, t_i - 21, 1));
		else if (t_i < 33) return _t.get(new BoardCoordinate(t_i - 28, t_i - 26, 2));
		else if (t_i < 37) return _t.get(new BoardCoordinate(t_i - 33, t_i - 30, 3));
		else return null;
	}