Dim ZahlenString As String = "123456789012345678901234567890"
        Dim ErgebnisString As String = ""
 
        For k As Integer = 0 To ZahlenString.Length - 1
 
          If (k > 0) And (k Mod 4 = 0) Then
 
            ErgebnisString += "."
 
          End If
 
          ErgebnisString += ZahlenString.Substring(k, 1)
 
        Next