Sub Worksheet_Activate()
Application.ScreenUpdating = False
Dim DL%, L%, i%, tablo, T
[B5:B10000].ClearContents
With Sheets("Feuil1")
DL = .[A65500].End(xlUp).Row: tablo = .Range("A2:C" & DL)
End With
ReDim T(1 To 3 * DL)
L = 1
For i = 1 To DL - 1
T(L + 0) = tablo(i, 1): T(L + 1) = tablo(i, 2): T(L + 2) = tablo(i, 3)
L = L + 3
Next i
[B5].Resize(UBound(T, 1)).Value = Application.Transpose(T)
End Sub