code: static String encodeCoordinates(Point2d[] points) {
          StringBuilder sb = new StringBuilder();
          sb.append("|(");
          for (Point2d point : points) {
              if (sb.length() > 2) sb.append(";");
              sb.append(DECIMAL_FORMAT.format(point.x));
              sb.append(',');
              sb.append(DECIMAL_FORMAT.format(point.y));
              sb.append(',');
          }
          sb.append(")|");
          return sb.toString();
      }
docs: Encode coordinates in a string.
  
  @param points points
  @return extended SMILES format coordinates