anchor.diff:              (Point(394, 202), Point(364, 218))
               (Point(410, 203), Point(383, 218))
               (Point(423, 204), Point(394, 219))
  -            (Point(439, 205), Point(417, 200))
  +            (Point(439, 205), Point(417, 220))
               (Point(455, 205), Point(431, 221))
               (Point(473, 206), Point(451, 222))
               (Point(489, 207), Point(467, 223))
  
positive.code:         Async.StartAsTask (loop [] iframeRect) |> ignore
  
      let testing () =
          BrowserAutomation.start ()
          let iframeRect = BrowserAutomation.iframeRect()
          let screenshot = BrowserAutomation.screenshot()
          let webcamImage = ImageProcessing.cropWebcamImage screenshot iframeRect
          WinForms.showMatInWinForm(webcamImage)
          OpenCvSharp.Cv2.WaitKey();
  
      [<EntryPoint>]
      let main argv = 
  
negative.code:         form.Controls.Add(pictureBox)
          System.Windows.Forms.Application.Run(form)
  
  //FIXME lots of OpenCV types are IDisposable, possibly eats memory at the moment
  module ImageProcessing =   
      open System.IO
      open Microsoft.FSharp.Reflection
  