let strate (d:dico) s (l:motif list) =
    let nv_motifs = List.flatten (List.map mouvements l) in

    let rec aux = function
    | [] −> []
    | m::suite when Hashtbl.mem d m −> aux suite
    | m::suite −> Hashtbl.add d m s; m :: aux suite
    in
    aux nv_motifs
;;