A nice simple one this week!  Which letter comes next in this series?  The answer is neither ‘I’ nor ‘X”.

I, X, X, X, I, X, I, I, I, I, I, I, I, I, I, _

As ever, please do NOT post your answers, but do feel free to say if you think you have solved it and how long it took.  Solution on Monday.

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. Given the clue that it’s not ‘I’ or ‘X’, it took about a minute. But, while my answer makes logical sense, and meets the requirements, it is actually wrong in common practice.

    1. That’s debatable. It’s not much of a practice anymore at all, except, dare I say, for pretentiousness and kitsch. That makes this a more tricky puzzle than it would’ve been a few decades ago.

    2. Well, it’s traditional. Although, interestingly, one of the most famous examples does not follow with tradition.

    3. Based on this comment, I presume we came up with the same answer, because I thought the same thing as soon as I realized what the pattern was.

  2. 5 or 10 minutes, and nothing. Then I guessed an answer on heuristic grounds, but didn’t have a stringent reason. Turns out it was correct. JFGI.

  3. Hmm, I’ve got the way of thinking, and I know what Richard thinks should the answer, however in many real-life cases I think the answer may be different from what Richard thinks, as he may have forgotten to check his model of the world with the real world 🙂

  4. I can see the answer you’re looking for, but as others have said, it’s wrong. The answer you’re looking for would come after this sequence:

    X, I, I, I, I, I, I, I, I, I, I, I, I, _

    1. I think i had a similar idea, but i dont know how long it took, i did not look at the clock…

  5. I think i have the answer. Took me about a minute, with some wrong possible answers coming to mind first ofcourse!

  6. Guessed at the answer, then took a few minutes working out WHY that was the answer.

    I have seen quite a few real-world examples where the answer is not correct, though.

  7. A couple of seconds to work out what sort of letter should be there, a few more seconds to spot the sequence in the first part of the series, but several minutes to realise what the whole sequence represented.

  8. The reason for the non-correct real-world examples reside in the way these elements have been manufactured…with the “uncorrect notation” it is possilbe to use 4 time the same mold/tool to manufacture all of them…

  9. Easy! A few seconds, and even before determining the exact sequence, I had a pretty good idea what the missing letter would be given the requirements. Of course, there are far too many commas in the sequence, but then again removing all the surplus ones would make it even less of a puzzle than it already is 🙂

  10. Absolutely not a single clue on this one, other than first thinking ‘Roman Numerals’ and having that lead me nowhere :/

    1. No?

      I’m starting to think I have completely misunderstood the puzzle this week, I don’t understand any of the comments

  11. Like all these puzzels they require some pre existing knowledge and like crosswords some experience of how Mr. Wiseman’s (sic) mind has wired his brain. Yes, you guessed it I have no idea of any answer. No doubt when the answer is revealed it’ll be like Poirot unmasking the killer – “Well if I’d know that!” Fun nonetheless. I,X,X,X says nothing to my mind & I can’t get Roman Numerals to fit, maybe the commas are equally important. I’ll just wait it out until Monday.

  12. Yeah I clocked the answer pretty quickly too,

    To those who have not seen it, I would not worry, these things are like crosswords, the more of them you do the easier they are, you learn the patterns…in fact something like IQ tests!

    Getting it quickly just proves you read things like this blog too much…

  13. That’s the sequence of stitches on my operation scar, but I’m no closer to guessing what’s next.
    Is it a question mark ?

  14. I have the answer. Took maybe 2 mins. The comments are largely ludicrous I’m afraid. It’s much simpler than people or making out and there is only one possible answer and it does not rely on obscure knowledge. I think some people may have over thunk this one!

    1. I don’t believe there is any question in the entire world that has only one possible answer. If you think there is, it is only because you can’t see the others, not because they don’t exist.

      Very zen, yes, I know

  15. Ah, I think I have it. Had to read a few comments first though.

    In the end I arrived at an answer that I sort of guessed at originally without really understanding the sequence.

    Good puzzle.

  16. I suspect this is a puzzle in which the young’uns are SEVERELY hampered. Nice to see there’s SOME mileage in being an old fart…

  17. In my personal environment here and now it IS an ‘I’, but I’ve seen the answer Richard probably has in mind when visiting London. Or I’m completely on a wrong track after several minutes.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s