docs: @Override
    public void appendPlotCommands(PlotBundle.Builder sb) {
      sb.append("set grid ");
      sb.append(yesNo(showXMajor)).append("xtics ");
      sb.append(yesNo(showXMinor)).append("mxtics ");
      sb.append(yesNo(showYMajor)).append("ytics ");
      sb.append(yesNo(showYMinor)).append("mytics ");
  
      sb.append(zIndex.asPlotCommand()).append(" ");
      majorLineStyle.appendPlotCommands(sb);
      sb.append(" , ");
      minorLineStyle.appendPlotCommands(sb);
      sb.append(" \nshow grid\n");
    }