The video you linked to has nothing at all to do with the parent one. You probably meant to reply to the topic, rather than the comment you actually replied to.
I suspect you're wrong, and that the connection between video and parent was that they were both Numberphile videos. An expanded comment might have read something like:
"Not only is today's Numberphile video potentially relevant, Numberphile actually directly addressed the article's exact topic several months ago."