docs: private MilestoneManager getHalfKilometerManager() {
          final Path arrowPath = new Path(); // a simple arrow towards the right
          arrowPath.moveTo(-5, -5);
          arrowPath.lineTo(5, 0);
          arrowPath.lineTo(-5, 5);
          arrowPath.close();
          final Paint backgroundPaint = getFillPaint(COLOR_BACKGROUND);
          return new MilestoneManager( // display an arrow at 500m every 1km
                  new MilestoneMeterDistanceLister(500),
                  new MilestonePathDisplayer(0, true, arrowPath, backgroundPaint) {
                      @Override
                      protected void draw(final Canvas pCanvas, final Object pParameter) {
                          final int halfKilometers = (int)Math.round(((double)pParameter / 500));
                          if (halfKilometers % 2 == 0) {
                              return;
                          }
                          super.draw(pCanvas, pParameter);
                      }
                  }
          );
      }