sub str_look {
   my $cells = shift;
   for my $p (@points) {
      # my $h = $p->[0] . ':' . $p->[1];
      # exists $cells->{$p->[0] . ':' . $p->[1]} or die;
      exists $cells->{ join(':', @$p) } or die;
   }
   exists $cells->{'notfound'} and die;
   exists $cells->{'notfound2'} and die;
   exists $cells->{'notfound3'} and die;
}