Neat solution...but when using 'B', it produces numbers greater than 6-bits can hold:
P:\test>perl
print join'|',
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
^Z
116|28|116|148|108|28|100|148|32|24|36|228|116|24|84|204
Switching to 'b' fixes that:
P:\test>perl
print join'|',
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
^Z
52|29|23|25|44|25|23|25|32|8|22|30|52|21|54|28
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