anchor.diff:    
     Map<String, dynamic> get properties => _props ;
     
  -  NumericalList asNumericalListX() {
  +  NumericalList asNumericalListXValues() {
       return new NumericalList.fromList( getXValues() ) ;
     }
     
  -  NumericalList asNumericalListY() {
  +  NumericalList asNumericalListYValues() {
       return new NumericalList.fromList( getYValues() ) ;
     }
   
  
positive.code:     return nl ;
    }
    
    NumericalList selectedSeriesByXValue( num xValue , [bool uniqueValues = false] ) {
      return selectedSeriesByXValues( xValue , xValue , uniqueValues ) ;
    }
    
    NumericalList selectedSeriesByXValues( num init, num end , [bool uniqueValues = false] ) {
      NumericalList nl = new NumericalList() ;
      
      for (var serie in this.series) {
        List<num> vals = serie.getXValues() ;
        
        for (num v in vals) {
  
negative.code:   
    ///////////////////////////////////////////////////////////////////////////////////////
    
    NumericalList selectSeriesXValues( [bool onlyEnabledSeries = true, bool uniqueValues = false] ) {
      NumericalList nl = new NumericalList() ;
      
      var series = onlyEnabledSeries ? this.seriesEnabled : this.series ;
      
      for (var serie in series) {
        List<num> vals = serie.getXValues() ;
        
        for (num v in vals) {
  