First, I dare you to read the comments on yesterday’s Paranormality article and not get depressed!

Second, here is the puzzle.  I like doughnuts.  Last week I bought a doughnut and wondered…..what is the largest number of pieces I can create by three straight cuts (and not rearranging the pieces between cuts)?

As ever, please do NOT post your answers, but do say if you think you have solved the puzzle and how long it took.

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.





  1. Not very good at this kind of puzzle, and for a moment I was depressed by the comments on the article. Then I remembered that I’m a born cynic, and all these people were just living down to my expectations.

  2. Ok think I have a respectable amount in about 3 minutes. Will find out monday if is correct.

  3. I think I’ve got it, in about a minute. But I’d like to see the proof of the correct answer.

    Now I need to sweep up the crumbs.

  4. Is the doughnut 3 dimensional, or do all the cuts have to be perpendicular to the plane we are viewing it on?

  5. Well Ive got an answer but as to whether or not Ive solved it I really don’t know. Look forward to finding out. Frankly I’m surprised it’s not a Ginger bread man…;-)

  6. “Has he ever seen ghost hunters show?”

    Well, I’m convinced. Those comments, epitomized by the one above, are well reasoned and erudite enough to turn this once skeptic into a believer.

    1. LOL! That snark made my night.

      Reading through comments like those (as well as the “we couldn’t get it published because they said there’d be no interest” comment) makes me embarrassed to identify as American. Did we stop teaching critical thinking skills in this country at some point?

  7. Doughnut you say? I didn’t see any doughnut! ~hurriedly wipes mouth~

    I have a 2d and 3d answer, and sticky fingers.

  8. Okay – kind of a Sisyphean task, but I put in a comment in your defense (#320). Not because I expect it’ll change anyone’s mind, but just to make myself feel better.


    Perhaps Wiseman is controlling my thoughts and forcing me to DO HIS BIDDING! NOOOOOO!!!

  9. Why would you cut up a perfectly good doughnut? They are not made to be shared.

    I dare anyone here to eat a sugar coated doughnut without licking their lips. It can’t be done.

  10. With three cuts I truly believe that I have managed to divide the doughnut into 279 pieces.

    Explain that, science…

    One number comes to mind straight away. I might go and buy some doughnuts and do some practical research before Monday.

  11. I got a decent answer in a minute or so for the 3D doughnut, but don’t want to put in the time to prove it’s the optimal solution mathematically. I believe proving the 2D solution is trivial, but don’t want to spend time doing that either.

  12. I think I have a 2d solution. As for the article, forget Ghost Hunters, can any sciency-science person explain Ghostwatch? Can you?

    Slightly depressing comments but completely expected.

  13. had a very nice very symmetric answer, but then disclovered an assymetric one havin an additional part.. so i am curios to see wich solution is the right one…

  14. I have an answer which I think is quite good, however some people may be a bit miffed at their share!

    Read and commented on those comments in yesterday’s thread, still depressed now 😦

  15. I don’t believe in doughnuts. Prove that they exist.
    (picks up doughnut)
    Well, they say the proof is in the pudding!
    As for how many pieces: not sure yet. Still thinking.

    1. Oh yes he is. He will probably turn out to have a wee bit of Scottish blood in him and will therefore not accept the name “doughnut”. Instead he will insist on using the name “doughring” and declare the puzzle void.

  16. About 10 minutes

    I first got a 2D and 3D answer in like 5 minutes.
    Then figured out a that I was contraining myself to only certain kinds of cuts, so ended up with a much better 2D answer, but didn’t bother trying to get another 3D answer by removing those same constraints 😀

  17. solution is fairly easy.
    Did you know that if you turn a torus inside out it remains a torus?
    I asked a ‘proper mathematician’ once and he drew diagrams to work it out.

  18. Been thinking a couple of minutes trying to see the cuts and all the pieces on my mind. I think I get it. 🙂

  19. I have a 2D answer and a 3D answer (about 20 seconds for the pair) and since both are larger than the “obvious”, I’m quite hopeful Richard will be posting one of them on Monday…

  20. Yumm. More tasty than the pizza and the horseshoe of a few weeks back, but following the same lines of thought, or rather cuts, in 2D or 3D.

  21. As we learned from the movie Young Frankenstein, “They’re all alike, all them scientists. They say they’re working for us, but what they really want is to rule the world!”
    Those were depressing comments indeed, all based on the idea that truth can be determined by opinion. There’s a lot of good science showing that people consider anything that violates their preconceptions to be from an unreliable source (
    The comments sounded kind of defensive to me; I think you hit a nerve there.

    1. Yes, it certainly does. I don’t know if you read it but it mentions how hard it is for scientists to guard against that.

    2. I agree it would be hard for the process of science to guard against the kind of ‘affective reasoning’ mentioned in that article. For example, if a majority of mainstream scientists posses a substantial affective bias against the existence of telepathy, then I don’t think peer review would stop such a bias from being expressed in the reviewing of a paper dealing with this topic. It would simply be a case of individual reviewers expressing their bias on an individual basis.

  22. I think the trick with the 3d version of the puzzle is to make one of the pieces a very narrow triangular pyramid that comes to a point within the torus and that passes completely inside the torus’s other side, but I’m having trouble holding the image in my mind so I can count the pieces.

  23. Perhaps if some of the commenters on that site read the book, they’d think differently.

    I like doughnuts too! The question I normally ask myself is “can I eat it without licking my lips?”.

    1. no, the more proof you give them, the more it reinforces their original beliefs.
      it’s called the backfire effect… : (

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