They are the same topic in the sense that the HN threads about them are going to lead to the exact same discussion. If you read https://news.ycombinator.com/item?id=43896978 and https://news.ycombinator.com/item?id=43901823, that should be clear - but if not, let me know and I'll try to clarify further.

"Show HN" is a separate thing entirely - it's true that the submitter of this article was the author (which is great), but that's not enough to make a post a Show HN (https://news.ycombinator.com/showhn.html).