# Puzzle hidden in revision history?

I recently came across the puzzle The 3 keys of the past, which only has this content:

## The key to this puzzle is the past

You don't need another hint...

I figured out where the rest of the puzzle was...

The actual "key" to the puzzle was in the question's revision history, in the "past."

That's clever, but is it really okay to "hide" the puzzle somewhere else and make finding the puzzle a puzzle?

If it's okay, where do we draw the line? Can a user do something similar and put the actual puzzle in a different question of theirs? What about hiding the "secret code" on a different website, and the first part of the puzzle is to find that website?

• I just came over to Meta to ask this. Seems gimmicky to me. – Dan Russell Jun 22 '16 at 13:35
• I'm not sure this is a great idea to allow, but I'm having some trouble expressing exactly why. – user20 Jun 22 '16 at 13:54
• Ahah i came to check meta to see if anyone was already on the way for "that was a good idea but please no clone" xD – Walfrat Jun 22 '16 at 14:47
• Only way I could even imagine considering revision history as fair play is if a puzzle mentions it specifically or at least has a solid clue that leads there. – humn Jun 22 '16 at 16:51
• Why don't you just improve the question by reverting the edit back to the original puzzle? Seems like it would be an improvement to me. – GentlePurpleRain Jun 22 '16 at 19:38
• – f'' Jun 23 '16 at 0:00

## This puzzle

Now that the puzzle in question has been solved, it seems to me that it really was just a gimmick without much value. As far as I can tell this puzzle could exist entirely as-is on the main question page. I think this is a poor choice because:

1. It doesn't add anything of value to the real puzzle.
2. It requires that a user understand revision histories and how to access them, which is certainly not true of all users.

And, if one more edit is made to this puzzle at some point, the "real" puzzle will fall entirely into the collapsed edits at the bottom of the revision history, further obscuring it.

## In general

At the same time, I could envision a situation where having to look carefully at the revision history would indeed provide some clues to a puzzle and thus be integral to solving it. Clues could be deleted bits, or timestamps of edits, or edit notes, or something like that. I'm sure that there would be a clever way to do this.

BUT I still think this should be strongly discouraged (i.e., downvoted) because of concern #2 above, as well as the fact that a puzzle maker does not have entire control over the revision history of his/her puzzle. Since others can edit the puzzle as well, it seems risky to put critical information in a revision history.

An aside...

If you want a good model of what kind of information can be hidden in edits/revision, click the "edit" button for this puzzle.

• re "envisioning a situation": puzzling.stackexchange.com/q/29954/10399 – Ian MacDonald Jun 23 '16 at 13:08
• I agree with your opinion: "it really was just a gimmick without much value."  But I'm also struggling to justify the opinion.  "It requires that a user understand revision histories and how to access them, which is certainly not true of all users."  How is this different from puzzles that include images that have steganographically hidden information?  Or ones that require higher mathematics?  Or programming languages?      See also Deliberate errors and anger at editors. – Peregrine Rook Jun 23 '16 at 22:52
• @PeregrineRook I get your point. I think that to some extent it's a matter of taste. My answer here isn't capital r Right, it's just accepted. To me, clues in the revision history, or in a user's profile, or hints in comments/chat...these aren't Wrong, I just find them in poor taste. I'd feel the same way about a question that required programming knowledge or advanced image manipulation to solve that wasn't appropriately tagged. A puzzle maker has an inherent advantage over the solver, and when solving I like to feel like the maker is leading me to a discovery, not manipulating me. – Dan Russell Jun 24 '16 at 1:28
• One of the first questions I engaged with on Puzzling was a riddle that seemed general, and was tagged only riddle but the solution required very specific knowledge of a specific video game. That one upset/annoyed me more. My reaction to this hidden-in-the-revision one was more of an eye roll. – Dan Russell Jun 24 '16 at 1:58

There is another reason why I don't like the idea of having to look in the edit history: in some cases looking in the history can spoil a puzzle. (E.g., the questioner makes a mistake and leaves something in the question that gives too much away, then of course notices and removes it -- but now looking in the history gives you a clue you shouldn't have had. Or the first version of a puzzle is just wrong -- e.g., insoluble -- and looking at how it changed to repair it gives things away.)

Because of this, I think the community norm should be that you don't go poking in the edit history of puzzles. And because of that, a puzzle where you're supposed to guess that that's the thing to do is encouraging solvers in a bad habit.

That wouldn't apply to a puzzle where you're explicitly told to go look in the history. But if there's an explicit instruction there, it seems to me the questioner might as well just put all the relevant stuff in the puzzle itself -- nothing is gained by putting it behind the minor inconvenience of checking the revision history.