For those who read the comments here on HN before reading the article, this thread contains more than just the self-enumerating tweet, it also talks about versions in multiple languages, how to search for such things, and a computer language that compiles to SAT.

There's more in the thread than just the curiosity.

I'm glad you pointed that out, since I thought it would just be a quote from Hofstadter's Metamagical Themas. The initial self-enumeration is just the kick-off for a more interesting thread that takes you on a bit of an emotional techy roller coaster.

I wrote a program in Lisp way back when that reproduces this kind of sentence, and allowed you to begin and end with any phrase bits you wish (eg: You might find it highly unlikely, but I can tell you that this sentence actually contains..., commas and a single exclamation mark to finish it off!) It was ugly but it worked. And thankfully didn't take 22 days since some word combinations did indeed lead to a fail.

I think it might have actually been Hofstadter's writing, and this exercise specifically, that got me interested in Lisp in the first place.