Changing line segment color in chart

[Michael M]

Hi All
I'm now completely intrigued.
A co-worker has created a line chart based on measurements for the year by month.
What has me fascinated is that if a segment of the series is positive ( or going up) it changes color. If it is going down it's different color again.
Can anyone out there enlighten me as to the code required to do this.
It's simply curiosity, I really can't see a genuine use for it in my business !!

Thank you for any inputs / comments.

 

[Michael M]

Ok, I've got myself to here, but the line in red, I believe is incorrect.
I've tried a few different variations, but no luck.
This code will activate the first segment of line but does nothing AND doesn't move to the next one either.

Sub ChangeColors()
    Dim i As Long
    Dim points(12) As Object
    ActiveSheet.ChartObjects("Chart 1").Activate
        For i = LBound(points) To UBound(points)
         With ActiveSheet.ChartObjects("Chart 1").Chart.SeriesCollection(1).points
            On Error Resume Next
            If points(i).Border.Value < 6 Then
                points(i).Border.ColorIndex = 4
            Else
                points(i).Border.ColorIndex = 8
            End If
        End With
        Next i
End Sub