This question is part of the best-puzzle award series.

What are your nominations for the best puzzles, here on Puzzling.SE, of the third quarter ( July / August / September) 2021?

Suggested guidelines for nomination:

  • Nominate each individual puzzle in a separate answer, so they can be upvoted/downvoted separately.

  • No more than 3 nominations per person.

  • Don't nominate your own puzzles.

  • Before you nominate a puzzle, check to see if someone else has already nominated it. If they have, then add to that nomination as a comment (or edit it) instead of nominating the same puzzle again.

  • In your nomination, explain what it is that (in your opinion) makes the nominated puzzle such a good one.

Some lists to help jog your memory (your nomination doesn't have to be from these lists):

Algorithmically selected "best of":

Best by votes/views:

Meta-meta issues:

Q: Is this kind of thing allowed on SE?
A: Yes, Photography SE and Sci-Fi & Fantasy SE do something very similar.

Q: What's the point?
A1: To highlight and encourage good practice in a way that goes beyond upvotes.
A2: To work towards building a 'hall of fame' of some of the best puzzles on the site (perhaps to reside on a future puzzling.SE blog) - think of it as our 'greatest hits album'.
A3: To prompt members to put forward their own reflections on what makes a high-quality puzzle.


3 Answers 3


Definition Resolution by noneuclideanisms

This puzzle hardly flew under the radar, since both the puzzle and the solution were both very well received...indeed, it tops the "most popular" list selected algorithmically. And rightly so.

It has an enigmatic presentation, but is approachable. The differing fonts of the words in the puzzle tantalized, and the boxes with each word gave a clue on what to do, but a very subtle one. And the way that the steps of the solution coalesced into a tight theme upon resolution is the sort of harmony that every setter should strive for.

Very fittingly, it was solved by our top rep user, Deusovi. I commented at the time: "This is a brilliant solve of a brilliant puzzle. +1". Time and perspective have not diminished this assessment in the slightest. Bravo Zulu!


Prove that π > 3 by Florian F

To me this is an example of great mathematical elegance. It seems obvious that such a geometric proof is possible but actually finding a cut of the three squares is still non trivial. Both highly upvoted answers are excellent. One can easily run into some messy algebra to see whether a proposed solution actually works or not but both of them manage to give easy geometric proofs with pretty pictures.


Decipher this message for instructions to decipher this message by SlowMagic

This was a wonder. It must have took time to find words with the same restrictions as the puzzle needed. The way it was solved, by working backwards, kind of gives everyone the feeling that the answer needs to be known before you can solve it. The comment in M Oehm's beautifully written answer was:

+1. It's quite fitting that this answer almost looks like you need to know the answer before you need to find the answer.

Along with that, it comes second in the top scoring questions of 2021 Q3, Third in the best answer score, and second in the popular puzzles list. After 2 months, the elegancy has still not faltered. Bravo SlowMagic!


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