As long as those 'n's match up, what's the trick?
It's a bit hard to know what you need without a single example.
My professor drew many pairs of matrices on a sheet of paper. He then asked "Which ones are in illegal positions?"
I believe I already know this but I want to make sure:
You can't have rows on the left, and columns on the right? However, the other way around is fine.
Just want to make sure.