$matrices = sequence(2,2,3);
  $threadable_rows = pdl([1,2],[4,5],[7,8])->(:,*1,:);
  print $threadable_rows x $matrices;

##</code><code>##

  $matrices = sequence(2,2,3);
  $wrong_rows = pdl([1,2],[4,5],[7,8]);
  print $wrong_rows x $matrices;