my $o = bless { a => 'A', b => 'B' }, "CLASS" ;

  show('main - pre ', $o) ;
  my $t = threads->new(\&proc, 'thread', $o) ; $t->join() ;
  show('main - post', $o) ;

  sub proc {
    my ($t, $x) = @_ ;
    $$x{z} = 'Z' ;
    show($t, $x) ;
  } ;

  sub show {
    my ($t, $x) = @_ ;
    printf "%20s: ", $t ;
    print "$x {", join(", ", map { "$_ => $$x{$_}" } sort keys %$x), "}\n" ;
  } ;

##</code><code>##

         main - pre : CLASS=HASH(0x15c2e88) {a => A, b => B}
              thread: CLASS=HASH(0x1adee98) {a => A, b => B, z => Z}
         main - post: CLASS=HASH(0x15c2e88) {a => A, b => B}


##</code><code>##

  my %s : shared = ( x => 'X', y => 'Y' ) ;
  my $o = bless \%s, "SHARE" ;

##</code><code>##

         main - pre : SHARE=HASH(0x15c4778) {x => X, y => Y}
              thread: SHARE=HASH(0x1825950) {x => X, y => Y, z => Z}
         main - post: SHARE=HASH(0x15c4778) {x => X, y => Y, z => Z}

##</code><code>##

  my $t = threads->new(\&make, a => 'A', b => 'B') ; my $o = $t->join() ;
  show('main', $o) ;

  sub make {
    my %s : shared = @_ ;
    my $m : shared = bless \%s, "MADE" ;
    show('thread', $m) ;
    return $m ;
  } ;

  use Scalar::Util qw(reftype) ;

  sub show {
    my ($t, $x) = @_ ;
    printf "%20s: %s", $t, $x ;
    my $r = reftype($x) || '' ;
    if ($r eq 'SCALAR') { print " = ", defined($$x) ? "'$$x'" : 'undef' ;                        } ;
    if ($r eq 'ARRAY')  { print " = [", join(", ", @$x), "]" ;                                   } ;
    if ($r eq 'HASH')   { print " = {", join(", ", map { "$_ => $$x{$_}" } sort keys %$x), "}" ; } ;
    print "\n" ;
  } ;

##</code><code>##

              thread: MADE=HASH(0x197d4e0) = {a => A, b => B}
                main: SCALAR(0x1712078) = undef