Bonjour Auberi,
Ci-dessous une possibilité
Sub TransformeMatrice()
Dim ShtS As Worksheet ' Feuille Source
Dim ShtD As Worksheet ' Feuille Destination
Dim dCol As Long, Col As Long
Dim dLig As Long, Lig As Long
Dim Ind As Long
' Définir les objets feuille
Set ShtD = ThisWorkbook.Sheets("Résultat attendu")
Set ShtS = ThisWorkbook.Sheets("Matrice")
dCol = ShtS.Cells(1, Columns.Count).End(xlToLeft).Column
dLig = ShtS.Range("A" & Rows.Count).End(xlUp).Row
Ind = 1
For Lig = 2 To dLig
For Col = 2 To dCol
ShtS.Cells(Lig, Col).Copy Destination:=ShtD.Range("A" & Ind)
Ind = Ind + 1
Next Col
Next Lig
End Sub
Edit : salut BsAlv