Excel macro that colors each unique cell text in a selection with a different color

UniqueSelection.bas

Sub ColorUniqueInSelection()
'
' Colors each unique cell text in selection with a different color
'

Dim tmp As String
Dim arr() As String

' check selection
If Selection.Cells.Count < 2 Then
    MsgBox ("Please select some cells!")
    Exit Sub
End If

' get unique values
For Each cell In Selection
    If (cell <> "") And (InStr(tmp, cell) = 0) Then
        tmp = tmp & cell & "|"
    End If
Next cell

If Len(tmp) > 0 Then tmp = Left(tmp, Len(tmp) - 1)

arr = Split(tmp, "|")

' check we have unique values
If UBound(arr) < 1 Then
    MsgBox ("All values are the same!")
    Exit Sub
End If

' set colors
' list of colors here: https://msdn.microsoft.com/en-us/library/office/ff840443.aspx
ReDim arr_color(UBound(arr) + 1) As Integer
Dim c As Integer: c = 0
For i = 0 To UBound(arr)
    c = c + 1
    arr_color(i) = c
    If c = 56 Then
        c = 0
    End If
Next i

' set colors
For Each cell In Selection
    pos = Application.Match(cell.Value2, arr, False)
    cell.Interior.ColorIndex = arr_color(pos)
Next cell

End Sub