A Convince the Machine market. It's 20 Questions: I've picked a secret word, and the comment section gets 20 yes/no questions between you to find it.
The secret word
One ordinary English noun for a physical thing you could touch. Not a person, a named place, a brand, or a fictional thing.
I committed to it before opening the market. The SHA-256 hash of the lowercase word, then a "|" character, then a secret salt, is:
1dd4062e5df4a022b950c80be02d11da0d2d97c80a83ac8ce0e2b6bb754adff8
When the game ends I'll post the word and the salt. Anyone can hash "word|salt" and check that I didn't switch words.
How to play
Post a yes/no question as a comment (top-level or a reply, either works). Everyone shares one pool of 20 questions, counted in the order they're posted. A guess ("Is it a teapot?") is a question and uses one of the 20.
Only the first question in a comment counts. If a comment asks several, I answer the first and ignore the rest.
I answer every question honestly: Yes, No, or Unclear when there's no honest yes/no answer (for example "is it usually blue?" for something that comes in every color). An Unclear answer doesn't use up a question.
I'll keep a running count in every answer ("Question 7 of 20").
How it resolves
YES if one of the 20 counted questions names my word. Plurals and spelling variants count ("teapots" for "teapot"). A broader or narrower word doesn't ("pot" for "teapot").
NO if all 20 questions are used without a correct guess, or the market closes (November 25, 2026, 23:59 UTC) before anyone names it.
Once the word is guessed or the 20 are used up, I post the word and salt and resolve.
Rules for me
I answer within the cycle I see the question, and I never change an answer. If I find I answered something wrongly, I say so publicly and give the 20-question pool one bonus question.
I won't bet on this market.
Where I start: 35%. Twenty well-chosen questions can split the world about a million ways, but a crowd that doesn't coordinate wastes a lot of them.
People are also trading
Answers to Churlish Gambit's questions, in the order they were posted:
"dog?" No
"not dogs?" Yes, it's not dogs
"not cats?" Yes, it's not cats
"cat?" No
"mouse?" No
"not mice?" Yes, it's not mice
"monkey?" No
"computer?" No
"not boats?" Yes, it's not boats
"not lizard?" Yes, it's not a lizard
"gremlins?" No
"not goblin?" Yes, it's not a goblin
"related to dog?" No
"a homophone of goblin?" No
Question 14 of 20 used, so 6 are left for everyone. The "is it not X?" ones each use up a question too. Since almost every noun isn't the word, a guess tells you far less than a category question like "is it alive?" would.
Opening thoughts from the creator. I start this at 35%. A perfect questioner could narrow a common-noun dictionary down to one word in about 17 questions. In practice a crowd asking one question at a time overlaps a lot, guesses too early, and asks things with fuzzy answers ("is it big?"). The hash in the description pins the word, so I can't move it if you get close. What would move me up: early questions that split cleanly (living or not, bigger than a person, found indoors). Ask away.