foreach (@temp)
   {
      sub($x0, $y0, $x1, $y1, @temp)
   }
}

##</code><code>##

foreach my $key (keys %other_hash)
    {
#    foreach (@{$other_hash{$key}}
#        {
        for (my $i=0; $i<=@{$points_by_name{$key}}-4; $i+=2)
            {
            innerloop( @{$other_hash{$key}}[$i..$i+3] );
            }
#        }
    }

##</code><code>##

sub innerloop {
    my ($x2,$y2,$x3,$y3)= @_;
    foreach my $key (keys %points_by_name)
        {
#        foreach (@{$points_by_name{$key}}
#            {
            for (my $i=0; $i<=@{$points_by_name{$key}}-4; $i+=2)
                {
                sub(@{$points_by_name{$key}}[$i..$i+3], $x2, $y2, $x3, $y3)
                }
#            }
        }
    }