Dim flowDoc As New FlowDocument()
Dim sec As New Section()

flowDoc.Background = Brushes.LightSlateGray
flowDoc.ColumnWidth = 2000
sec.Background = Brushes.DarkMagenta
sec.Margin = New Thickness(0)
sec.Padding = sec.Margin

Dim defPar1 As New Paragraph(New Run("Default paragraph."))
Dim defPar2 As New Paragraph(New Run("Default paragraph."))
Dim defPar3 As New Paragraph(New Run("Default paragraph."))
Dim defPar4 As New Paragraph(New Run("Default paragraph."))
defPar4.Background = Brushes.White
defPar3.Background = defPar4.Background
defPar2.Background = defPar3.Background
defPar1.Background = defPar2.Background

Dim marginPar As New Paragraph(New Run("This paragraph has a magin of 50 pixels set, but no padding."))
marginPar.Background = Brushes.LightBlue
marginPar.Margin = New Thickness(50)
Dim paddingPar As New Paragraph(New Run("This paragraph has padding of 50 pixels set, but no margin."))
paddingPar.Background = Brushes.LightCoral
paddingPar.Padding = New Thickness(50)
Dim marginPaddingPar As New Paragraph(New Run("This paragraph has both padding and margin set to 50 pixels."))
With marginPaddingPar
    .Background = Brushes.LightGreen
    .Margin = New Thickness(50)
    .Padding = marginPaddingPar.Margin
End With

sec.Blocks.Add(defPar1)
sec.Blocks.Add(defPar2)
sec.Blocks.Add(marginPar)
sec.Blocks.Add(paddingPar)
sec.Blocks.Add(marginPaddingPar)
sec.Blocks.Add(defPar3)
sec.Blocks.Add(defPar4)
flowDoc.Blocks.Add(sec)