VBA Code for PowerPoint Dynamic Clock

Question

I want to create a dynamic clock in PowerPoint and have it show up in the same location on all slides. Below is the code I have been working on to create the dynamic clock.

Instead of "Do Until 1 < 0", I probably want something along the lines of "Do Until PowerPoint Exit Slideshow Mode" but I'm not sure how to do that.

I tried creating a shape in the PowerPoint slide master, but I'm not sure how to define that shape in the Shapes() portion of the code. I've only ever been able to get the clock to run in Shapes (1) and Shapes(2) - i.e. the default text boxes in the slides.

Sub OnSlideShowPageChange()
  Dim time As Date
  Dim count As Integer

  time = Now()

  Do Until 1 < 0
    DoEvents

    With
      ActivePresentation.Slides(SlideShowWindows(1).View.CurrentShowPosition).Shapes(1).TextFrame.TextRange
      .Text = Format((Now()), "hh:mm:ss")
    End With
  Loop
End Sub