"- You stupid.
– No, I'm not.
– What's nine plus ten?
– Twenty one.
– You stupid."
In 2013, defunct video-sharing app Vine catapulted this odd exchange to virality (archived, of course, on YouTube).
Eight years later, the video hasn't been forgotten. This incorrect math answer left an indelible mark on culture, and a Twitter account has gained nearly 100,000 followers by doing a daily countdown to 9/10/21.
In a nod to the communicative property, the account announced they'd celebrate 10/9/21 as well.