parameter nat;
storage (list nat);
code { DUP;                     # Duplicate the storage and parameter
       CAR;                     # Extract the parameter
       DIP{CDR};                # Extract the storage
       DUP;                     # Duplicate the parameter
       DIP{CONS};               # Add the first instance of the parameter to the list
       CONS;                    # Add the second instance of the parameter to the list
       NIL operation; PAIR}     # Finish the calling convention