[andrei-akopian]

I always notice these patterns on HN.

Always gives me dejavu and that feeling you get when you suddenly start encountering some new topic or word in suspiciously large amounts.

Some big sciency/techy outlet puts something interesting out, and suddenly related topics start popping up everywhere else. I am guilty of a few of these myself.

[ryankrage77]

https://en.wikipedia.org/wiki/Frequency_illusion

[aembleton]

It might also be that more QR code stuff gets upvoted as people have it in their minds after watching the video.