use 5.016;
use Data::Walk;
use Storable qw/dclone/;
use Data::Dumper::Concise;

my %h3 = ( 
    a => [ 
        { b => { c => [qw/d e/] } },
        { f => { g => 'h' } },
    ],  
);

my @found;

my %paths; 
my @path;
my $walker = sub {
    say qq{Visit depth $Data::Walk::depth, index $Data::Walk::index } . (ref $_ ? '' : qq{"$_"}) . qq{ Seen: $Data::Walk::seen};
    if ($Data::Walk::type eq 'HASH') {
        if ( !ref $_ && $Data::Walk::index % 2 == 0 ) { 
            @path = () if $Data::Walk::depth == 2;
            push @path, $_; 
        }   
        elsif (@path) {
            my $key = join '.', @path;
            $paths{$key} = ref $_ ? dclone $_ : $_; 
        }   
    }   
    elsif ($Data::Walk::type eq 'ARRAY') {
        my $key = join '.', @path, $Data::Walk::index;
        $paths{$key} = $_; 
        pop @path if $Data::Walk::index == $#{$Data::Walk::container} && !ref $_; 
        push @path, $Data::Walk::index if ref $_; 
    }   
    else { say qq{Something else here!} }
    1;  
};
%paths = (); 
@path = (); 
walk $walker, \%h3;
print Dumper \%paths;