$_ = [
    [
        [ [ {}, [] ], { 73, '01110111', 1000, '11100101' }, [ [] ] ],
        {
            1,
            '01111110',
            72,
            '00011010',
            64,
            '011001000011111001111010',
            8,
            '00000100',
            9,
'0101010100010000000111111010001010100000000010100011000001000100101010100',
            65,
            '011100001001010100000001'
        },
        [ [] ]
    ]
];
(%_) = %{ ${ ${ $_; }[0]; }[1]; };

##</code><code>##

undef $_;
%_ = (
            1 => '01111110', # '~'
            72 => '00011010', # 'X'
            64 => '011001000011111001111010', # '&|^'
#                  012345678901234567890123
            8 => '00000100', # ' '
            9 =>
'0101010100010000000111111010001010100000000010100011000001000100101010100',
#0123456789012345678901234567890123456789012345678901234567890123456789012
#          1         2         3         4         5         6         7  
            65 => '011100001001010100000001'
#                  012345678901234567890123
);

##</code><code>##

$s = eval {
    do {
        $O = 0, $C = 0, $t = 'This is my 100th PM post';
#                             012345678901234567890123
        sub {
            $O++, $C = @_ ? $C : eval
# { do { my $k =
pack( 'b*',
                vec( pack( 'b*', $_{64} ), $O - 1, 1 ) ? $_{1} : $_{8} )
              . $C
              . pack( 'c', vec( pack( 'b*', $_{64} ), ( $O - 1 ) % 3, 8 ) )
              . pack( 'b*',
                vec( pack( 'b*', $_{64} ), $O - 1, 1 ) ? $_{8} : $_{1} )
              . vec( $t, $O - 1, 8 );
# print " $k"; eval $k; } }
          }

      }
};

##</code><code>##

$o = pack( 'b*', $_{9} );
foreach $_ ( 0 .. unpack( '%b*', $o ) - 2 ) {
# 16 bit checksum = 25, - 2 = 23

##</code><code>##

    $c = $_ - ( ( $_ - $_ % 4 ) / 4 + ( $_ % 4 ? 1 : 0 ) );
# print $c;
# 0 0 1 2 3 3 4 5 6 6 7 8 9 9 10 11 12 12 13 14 15 15 16 17
    $i =
      vec( $o, $c, 4 ) + ( vec( $o, $c + 1, 4 ) << 4 ) >> 4 - $_ % 4 - 4 *
      ( $_ % 4 ? 0 : 1 );
# >> 0 3 2 1 0 3 2 1 0 3 2 1 0 3 2 1 0 3 2 1 0 3 2 1
# print $i;
# 170 21 34 4 128 16 62 47 69 8 21 2 0 0 20 98 12 1 8 17 82 10 21 2
# print $i % 16; # == vec( pack( 'C', $i ), 0, 4 )
# 10 5  2  4  0  0  14 15 5  8  5  2  0  0  4  2  12 1  8  1  2  10 5  2
# 0101  0100  0000  0111  1010  1010  0000  0010  0011  0001  0100  1010   

#    1010  0010  0000  1111  0001  0100  0000  0100  1000  1000  0101  0100
# J  u  r  t        n  o  u  h  e  r     P  d  r  l  a  h  a  b  j  e  r
#       *        *        *                 *        *        *  *

##</code><code>##

    $i += $i % 2 ? -1 : 1 # $i ^= 1
      if ( $_ + 1 ) % 12 and not(( $_ + 1 ) % 3)
      or $_ + 1 == 22;
# print $i;
# 170 21 35 4 128 17 62 47 68 8 21 2 0 0 21 98 12 0 8 17 83 11 21 2
# print $i % 16;
# 10 5 3 4 0 1 14 15 4 8 5 2 0 0 5 2 12 0 8 1 3 11 5 2
# J  u s t   a n  o  t h e r   P e r l    h a c k  e r

##</code><code>##

    $T =
      vec( pack( 'C', $i ), 0, 4 ) + vec( pack( 'b*', $_{65} ), $_, 1 ) * 16 +
      32;
# print $T;
# 42 53 51 52 32 33 46 47 52 40 37 50 32 48 37 50 44 32 40 33 35 43 37 50
# 0  1  1  1  0  0  0  0  1  0  0  1  0  1  0  1  0  0  0  0  0  0  0  1
# J  u  s  t     a  n  o  t  h  e  r     P  e  r  l     h  a  c  k  e  r
# *  1  2  3  4  5  6  7  8  9  10 11 12 *  1  2  3  4  5  6  7  8  9  10

##</code><code>##

    print pack( 'c', ( $T += $T == 32 ? 0 : 64 ) -= $_ % 13 == 0 ? 32 : 0 );

##</code><code>##

#    &$s; # independent of rest of loop, unrolled
}
# print ' ',
&$s for 0..23;
# 00   14294967295  2105  38   44294967263  573   68   74294967263  877
# 94   104294967291 1153  120  134294967295 14116 1520 164294967263 17112
# 1813 194294967282 20125 2116 224294967295 23116

##</code><code>##

print pack( 'c', &$s(1) ^ unpack( 'c', pack( 'b*', $_{72} ) ) );