When n = 2, this is the only way to add a line that meets the requirements (the number of four corners of any rectangle is not exactly the same):

0 0 1 1 0 1

1 1 0 0 0 1 (0 and 1 are interchangeable, but the effect is the same).

Note: If three of the six columns are the same (for example, all three columns are 0 1 (see columns)), you will not be able to add the rows that meet the requirements.

The added line (that is, the third line) has two situations: 011or 01100.

But you can't add another line.