private static Line below(LinkedList<Line> tLines, Line l) {
        int index = -1;
        for (Line l0 : tLines) {
            if (l0 == l) {
                index = tLines.indexOf(l);
                break;
            }
        }
        if (index < tLines.size() - 1) {
            return tLines.get(index + 1);
        } else if (index == tLines.size() - 1) {
            return null;
        }
        return null;
    }