It's easy to tell imo in part because of how terse the sentences are:

`Obvious in hindsight.`

`The clock never jumps.`

`No lookahead, no undo.`

`A real kick pattern is not a clock.`

>Larger point: I am so sick of HN comment sections filling up with obligatory comments speculating about whether a post is AI-written.

Gotta disagree wholeheartedly with that - using AI to write for you is really fucking annoying as a reader. It screams to me that the "author" feels the reader's time is worthless, and it homogenizes language in a way that is troubling to say the least.