A couple of days ago, I caught the ending of David Marks' Woodworks program and he was doing a burl veneer table. He briefly showed how he used a mirror to figure out how to position the burl, or something like that. I missed it, and it was just him going over the highlights.
What exactly was he doing with the mirror? Is it a common practice or technique? I'm just curious and would like to learn about it some more.
TIA,
Mike Dembroge