$pg->owns( qw/ $Who gold / );

##</code><code>##

    my $a = shift @important;
    while( my $z = shift @important ) {
        return if !$self->_check_path($predicate_id,$a,$z,@args[$a,$z]);
        $a = $z;
    }
    return 1;

##</code><code>##

    sub _check_path {
        my ( $self, $predicate, $lvl1, $lvl2, $arg1, $arg2 ) = @_;
        return 1 if
            exists $self->{_arg_levels}{$predicate}[$lvl1]{$arg1}[$lvl2]{$arg2};
        return; # nope, didn't find it
    }

##</code><code>##

  $pg->add_fact( owns => qw/ Ovid socks / );
  $pg->add_fact( gives => qw/ grep grief Ovid / );