Isn't https://www.youtube.com/watch?v=RsqCySU4Ln0 (linked above) that?

Here's what we always tell founders about demo videos: "What works well for HN is raw and direct, with zero production values. Skip any introductions and jump straight into showing your product doing what it does best. Voiceover is good, but no logos or music!"

My bad, totally missed the link in the text post. I clicked on 'watch video' on the Poly website