my @fields=
     unpack "C*",    # 16 6-bit numeric values
     pack   "B6"x16, # string of 16 bytes, each  holding a 6-bit value
     unpack "a6"x16, # 16 6-character base-2  strings
     unpack "B*",    # 96-character base-2  string
     "twelve bytes"; # 12-byte packed string

my $string=
     pack   "B*",    # 12-byte packed string
     pack   "a6"x16, # 96-character base-2  string
     unpack "B6"x16, # 16 6-character base-2  strings
     pack   "C*",    # string of 16 bytes, each  holding a 6-bit value
     @fields;        # 16 6-bit numeric values