anchor.diff:  
     /// Counter for saving files
     let imageCounter = 
  -    let count = ref 0
  -    (fun () -> incr count; !count)
  +      let mutable count = 0
  +      fun () ->
  +          count <- count + 1
  +          count
   
     let transformation (value:obj, typ:System.Type) =
       match value with 
  -    // | :? System.Drawing.Image as img ->
  -    //     // Pretty print image - save the image to the "images" directory 
  -    //     // and return a DirectImage reference to the appropriate location
  -    //     let id = imageCounter().ToString()
  -    //     let file = "chart" + id + ".png"
  -    //     ensureDirectory (output @@ "images")
  -    //     img.Save(output @@ "images" @@ file, System.Drawing.Imaging.ImageFormat.Png) 
  -    //     Some [ Paragraph([DirectImage ("", root + "/images/" + file, None, None)], None) ]
  -
       | :? GoogleCharts.GoogleChart as ch ->
           // Just return the inline HTML of a Google chart
           let ch = ch |> XPlot.GoogleCharts.Chart.WithSize(700, 400)
           Some [ InlineBlock (ch.GetInlineHtml(), None) ]
  -
       | :? Plotly.PlotlyChart as chart ->
  -        // Just return the inline HTML for a Plotly chart
  -//        let name = 
  -//          match fig.Layout with
  -//          | Some ly -> ly.title
  -//          | None -> sprintf "XPlot Generated Chart %d" (imageCounter())
  -//        fig.Width <- 600
  -//        fig.Height <- 300
  -//        Some [ InlineBlock (fig.GetInlineHtml(name)) ]
           Some [ InlineBlock(chart.GetInlineHtml(), None) ]
  -    | :? D3.ForceLayoutChart as chart -> Some [ InlineBlock(chart.GetHtml(), None) ]
  -
  +    | :? D3.ForceLayoutChart as chart ->
  +      Some [ InlineBlock(chart.GetHtml(), None) ]
       | SeriesValues s ->
           // Pretty print series!
           let heads  = s |> mapSteps sitms fst (function Some k -> td (k.ToString()) | _ -> td " ... ")
  
positive.code: 
  /// Checks if the given directory exists. If not then this functions creates the directory.
  let ensureDirectory dir =
    let di = new DirectoryInfo(dir)
    if not di.Exists then di.Create()
  
  /// Combine two paths
  let (@@) a b = Path.Combine(a, b)
  
negative.code:         [ InlineMultiformatBlock(("<div class=\"deedleseries\">", None), ("\\vspace{1em}", None))
            TableBlock(Some ((td "Keys")::heads), AlignDefault::aligns, [ (td "Values")::row ], None) 
            InlineMultiformatBlock(("</div>", None), ("\\vspace{1em}", None))] |> Some
      | :? IFrame as f ->
          // Pretty print frame!
          { new IFrameOperation<_> with
              member x.Invoke(f) = 
                  let heads  = f.ColumnKeys |> mapSteps fcols id (function Some k -> td (k.ToString()) | _ -> td " ... ")
                  let aligns = f.ColumnKeys |> mapSteps fcols id (fun _ -> AlignDefault)
                  let rows = 
                    f.Rows |> Series.observationsAll |> mapSteps frows id (fun item ->
                      let def, k, data = 
                        match item with 
                        | Some(k, Some d) -> "N/A", k.ToString(), Series.observationsAll d |> Seq.map snd 
                        | Some(k, _) -> "N/A", k.ToString(), f.ColumnKeys |> Seq.map (fun _ -> None)
                        | None -> " ... ", " ... ", f.ColumnKeys |> Seq.map (fun _ -> None)
                      let row = data |> mapSteps fcols id (function Some v -> formatValue floatFormat def v | _ -> td " ... ")
                      (td k)::row )
                  [ 
                    InlineMultiformatBlock(("<div class=\"deedleframe\">", None),("\\vspace{1em}", None))
                    TableBlock(Some ([]::heads), AlignDefault::aligns, rows, None) 
                    InlineMultiformatBlock(("</div>", None), ("\\vspace{1em}", None))
                  ] |> Some }
          |> f.Apply
      | _ ->
          None 
      
    // Create FSI evaluator, register transformations & return
    let fsiEvaluator = FsiEvaluator() 
  