Sub EssaiSylvanu()
Sheets("Feuil1").Select
If ActiveSheet.Name <> "Feuil1" Then Exit Sub
If IsEmpty([A1]) Then Exit Sub
Sheets("Entete").Select
Worksheets("Feuil2").Columns("A:C").ClearContents
Dim Tin, Tout, D1, D2%, Indice%, L%, C%
Tin = Sheets("Feuil1").[A1].CurrentRegion
D1 = Int((UBound(Tin) / 3) * (1 + UBound(Tin, 2)))
Indice = 0
ReDim Tout(D1, 2)
For L = 1 To UBound(Tin) Step 3
For C = 1 To UBound(Tin, 2)
Tout(Indice, 0) = Tin(L + 0, C)
Tout(Indice, 1) = Tin(L + 1, C)
Tout(Indice, 2) = Tin(L + 2, C)
Indice = Indice + 1
Next C
Next L
Sheets("Feuil2").[A1].Resize(UBound(Tout, 1), 1 + UBound(Tout, 2)) = Tout
End Sub