sub closer_to_origin {
   my ( $start, $test ) = @_;

   my $sd = 0; $sd += $_*$_ foreach (@$start);
   my $td = 0; $td += $_*$_ foreach (@$test);

   return ( $td < $sd );
}

##</code><code>##

my @closer_ns = grep { closer_to_origin( \@point, $_ ) } @n;