private void breakLine(Ring r, List<LineString> lines) {
for (int i = 0, n = lines.size(); i < n; i++) {
LineString line = lines.get(i);
PointLineBag bag = line.intersection(r);
List<LineString> newLines = bag.breakLine(line);
if (newLines.size() > 1) {
lines.remove(i);
lines.addAll(newLines);
return;