Ask HN: Quiz or test shared on HN you only take once
Quiz or challenge shared on HN. User allowed to take test only once, or rather something about the test made subsequent attempts not valid. (You learn something about the test as you take it.) At the end you receive a percentile score relative to other users. I don't exactly remember the content or what was being tested. Possibly it had something to do with LLMs.
I believe I found it: https://nicholas.carlini.com/writing/llm-forecast/question/C...
HN's not Google
Questions like mine ("help me find it") occasionally posted here. I believe "Ask HN" is the appropriate section.