#! perl -slw
use strict;
use threads;
use threads::shared;
use Data::Rmap;

sub thread {
    my( $hashref ) = @_;
    rmap{
        print "$_";
    } $hashref;
}

my %hash : shared;

$hash{ leaf } = 'fred';
$hash{ L1 } = &share( {} );
$hash{ L1 }{ leaf } = 'wilma';
$hash{ L1 }{ L2 } = &share( {} );
$hash{ L1 }{ L2 }{ leaf } = 'bam bam';
$hash{ L1 }{ L2 }{ L3 } = &share( {} );
$hash{ L1 }{ L2 }{ L3 }{ leaf } = 'flintstone';

threads->create( \&thread, \%hash )->join;

__END__
P:\test>junk2
fred
wilma
bam bam
flintstone