sub seqsub(&) { $_[0] }

##</code><code>##

    sub count_zipped_combo_vals {
        my %counts;
        seq_foreach_from_spec( \@_, sub {
            seq_foreach(
                seq_zip( ( map seq(split//), @_ ) ),
                sub { $counts{"@_"}++ }
            )
        });
        \%counts;
    }

##</code><code>##

    # a few problem cases to try

    my @site1 = qw( AATKKM aatkkm        );
    my @site2 = qw( GGGGGG gggggg        );     
    my @site3 = qw( XXXXXX ++++++ yyyyyy );
    # ... and so on ...

    my @sites = \( 
        @site1, @site2, @site3, # ... and so on ...
    ); 

    # try 1-, 2-, and 3- array cases
    print Dumper( count_zipped_combo_vals( @sites[0..$_] ) )
        for 0 .. $#sites;


    # $VAR1 = {
    #           'A' => 2,
    #           'k' => 2,
    #           'a' => 2,
    #           'M' => 1,
    #           'T' => 1,
    #           'K' => 2,
    #           'm' => 1,
    #           't' => 1
    #         };
    # $VAR1 = {
    #           'K G' => 2,
    #           'A G' => 2,
    #           'm g' => 1,
    #           'a g' => 2,
    #           'A g' => 2,
    #           'M G' => 1,
    #           'k g' => 2,
    #           'k G' => 2,
    #           'T G' => 1,
    #           'a G' => 2,
    #           'm G' => 1,
    #           't G' => 1,
    #           'K g' => 2,
    #           'M g' => 1,
    #           't g' => 1,
    #           'T g' => 1
    #         };
    # $VAR1 = {
    #           't G y' => 1,
    #           'T G +' => 1,
    #           'K G X' => 2,
    #           'a G X' => 2,
    #           'm G +' => 1,
    #           'a G +' => 2,
    #           'T g y' => 1,
    #           'm g +' => 1,
    #           'a g +' => 2,
    #           'k G X' => 2,
    #           'a g X' => 2,
    #           'm g X' => 1,
    #           'T g X' => 1,
    #           't G +' => 1,
    #           'M G y' => 1,
    #           'k g y' => 2,
    #           't g y' => 1,
    #           'm G X' => 1,
    #           't G X' => 1,
    #           'K G +' => 2,
    #           't g +' => 1,
    #           'a g y' => 2,
    #           'T G X' => 1,
    #           'm g y' => 1,
    #           'm G y' => 1,
    #           'A G X' => 2,
    #           'M g +' => 1,
    #           'k g +' => 2,
    #           'k g X' => 2,
    #           'A g X' => 2,
    #           'A g +' => 2,
    #           'M g y' => 1,
    #           'k G +' => 2,
    #           'a G y' => 2,
    #           'M G +' => 1,
    #           'A g y' => 2,
    #           'K g X' => 2,
    #           'K G y' => 2,
    #           'K g y' => 2,
    #           'K g +' => 2,
    #           'k G y' => 2,
    #           'A G y' => 2,
    #           'T g +' => 1,
    #           't g X' => 1,
    #           'M G X' => 1,
    #           'M g X' => 1,
    #           'T G y' => 1,
    #           'A G +' => 2
    #         };