Recently a question was posted which is a puzzle by a popular Math teacher. Not to my surprise, answers existed on the net at several different places.

I have seen this before also. Reposting puzzles from other sources whose unique answers already exist- is that against any site policy, even though attribution is given? There are literally dozens of puzzle sites with already existing answers.

  • $\begingroup$ One thing to note is that "chestnuts" (such as the blue-eyes problem) are on-topic here, even though there are many solutions elsewhere. $\endgroup$
    – bobble
    Dec 22, 2020 at 16:06
  • $\begingroup$ @bobble I am thinking about policy on this site. As you well know there are many puzzles with answers on the Net. Is the general policy that they are OK to post as long as there is attribution? What is the point if a "unique" answer exists and already posted on the Net? This site could then be flooded with such puzzles. $\endgroup$
    – DrD
    Dec 22, 2020 at 17:19

1 Answer 1


Our aim here, when posting puzzles, is not to collect every puzzle and riddle into one place. It is more about sharing either original puzzles, or ones that are very interesting that most people probably wouldn't have seen, with a community of puzzle fans. Attempting to collect every puzzle here is an impossible task, and not one we want done anyway.

Having said that, there is no policy against posting puzzles that have been asked and answered elsewhere simply because they've been asked and answered elsewhere. As long as a puzzle fits all the other criteria for being posted to this site, its presence elsewhere on the Web is not a barrier to posting it here.

If you ...

  • have permission to post someone else's content
  • provide proper attribution for it
  • are not merely leveraging other content creators' work for your own visibility, reputation, etc.
  • are posting to share an interesting, thought-provoking, and/or otherwise noteworthy or overlooked puzzle

then by all means, post away, even if it's something asked and answered elsewhere.
If you're not ticking all the boxes there, though, please consider carefully why you're posting, before posting.

  • $\begingroup$ What about situations where permission is hard to get? For example, there's a very interesting logic grid problem I found in an old magazine - I have no way to ask for permission to post. Would fulfilling the other three bullet points be enough? $\endgroup$
    – bobble
    Jan 7, 2021 at 5:26
  • $\begingroup$ Fair use covers a lot of territory. Moderators do not police copyright. For content where the content creator is unknown or unreachable and there isn't good reason to think they do not want their content redistributed, you can probably get away with it; but I'll stop short of saying it's not an issue. If that sounds like a hazy answer, that's because it's a hazy issue. :) $\endgroup$
    – Rubio Mod
    Jan 7, 2021 at 5:33
  • 1
    $\begingroup$ It is interesting. When a question is posted on this site and is a duplicate of another question on this very site it is closed as a duplicate saying an answer exists. But if the same question is a duplicate on another site, that is OK? $\endgroup$
    – DrD
    Jan 7, 2021 at 13:27
  • $\begingroup$ @DrD If we already have a question and answer on this very site, there's no benefit to having it here twice (it's actually harmful: ideally all good answers to a given question should appear in a single place, not spread across two or more question postings). Hence, such duplicates are closed, as is the norm for all of Stack Exchange. If the same question happens to exist beyond the confines of our site, there's no guarantee it will remain there, or that the answer(s) elsewhere are correct; additionally, our users may not have seen it. There's no harm, and it may benefit, to also have it here. $\endgroup$
    – Rubio Mod
    Jan 7, 2021 at 15:56

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