use Thread;$| = 1;if (@ARGV) {    srand($ARGV[0]);} else {    my $seed = $$ ^ $^T;    print "Randomising to $seed\n";    srand($seed);}sub whoami {    my ($depth, $a, $b, $c) = @_;    my $i;    print "whoami ($depth): $a $b $c\n";    sleep 1;    whoami($depth - 1, $a, $b, $c) if $depth > 0;}sub start_foo {    my $r = 3 + int(10 * rand);    print "start_foo: r is $r\n";    whoami($r, "start_foo", "foo1", "foo2");    print "start_foo: finished\n";}sub start_bar {    my $r = 3 + int(10 * rand);    print "start_bar: r is $r\n";    whoami($r, "start_bar", "bar1", "bar2");    print "start_bar: finished\n";}$foo = new Thread \&start_foo;$bar = new Thread \&start_bar;print "main: exiting\n";