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Physics World at 25: Puzzle 4

By Louise Mayor

Prepare to be perplexed by the fourth and penultimate brainteaser in the Physics World at 25 Puzzle. #PW25puzzle


Which food is, unusually, mentioned in the third of these well-known laws of physics?

KEPLcRS FIddT iAW ecYc hHec adu OrBug ey hVbit PLsNgm oS ff fjagnhf WenH bbg iUq sg Odh cF fme dfCv

egmyffa kijpNd vql DffmqszgS doW kHd garbtnpgmvbd dF kx nBJdCe xdLjcpe co uic McaS knD jHe FjRcE ACgecG ON IT


Enter your answer here

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  1. Please be a good sport and DO NOT post the answer in the comments.

    By all means discuss the puzzle in the comments. You can check whether your answer is correct using the box above. Happy puzzling!

  2. James

    No ranking this week?

  3. Tim P

    Got the answer but I’ve no idea why it’s correct! #5

  4. C McCormack

    I think it’s safe to say I’m terrible at ciphers.
    got every single word except the answer word purely through knowing the laws and filling the blanks, but I can see absolutely no pattern in the relationship between solved and unsolved letters

  5. Angus Mclellan

    Stuck in the same position as ?McCormack

  6. Peter Wishart

    Was in the same position as C McCormack and Angus McLellan.. then I guessed. #17. Need to explain my working somehow!!

    • Mark

      Was also in the same position as C McCormack and Angus McLellan.. then I guessed.

      Still in that position

  7. Chris

    #19. Managed to decipher everything by guessing the laws, but couldn’t see any kind of link to the letters. Technically I got the letters for my answer from within the puzzle, but it seemed more like guesswork than a proper solution. Would be interested to know the proper approach!

  8. Old Bob

    #20 Count me in with the intelligent guessers. Now have the rest of the week to work out the actual cipher. Progressing nicely though: #2500ish, #601, #39, #20.

  9. C McCormack

    i seem to be terrible at guessing too, can’t come up with the goods!

  10. Tim H


    Worked it out in a couple of hours. It was good fun this one.

  11. I would recommend working out the puzzle in order to come to the solution as the most satisfying way to go. (Rather than guessing at the answer and then working backwards.)

  12. MS

    For me it was the double coded letters that provided the inspiration for the codes.

  13. Rob Le Grove

    Wow, was scratching my head over that last bit for about an hour, very clever puzzle! #39

  14. Leigh

    I’ve got the laws, but I’m a bit baffled by the code. I have a long list of discounted theories so far. Hopefully it won’t take me all night to come up with a working code!

  15. Paul

    #45. I enjoyed this.

  16. justin davies

    #48. wow that was tricky. was number two last week, so going backwards :). What do I do now with this ridiculous spreadsheet I just built?! lol.

  17. KOL

    any hint ?!

    • Paul

      KOL – I agree with MS that the places where the coded letter is repeated are the starting point. And remember that this is a meal of three courses.

  18. Michael McLaughlin

    Shouldn’t “xdLjcpe co uic” in the second law be xdLjcph co ujc”. I’m struggling with third law.

    • Steve H

      Yes, I think you’re right there. And if you’ve got that far, you can’t be far away from the third either. It’s not very far from the method of the first two.

      • Steve H

        Apologies, terrible English, and sorry, I need to check again, but I think the code is right actually. Why did I doubt? It depends on whether you’ve guessed one three word correctly. I, like you, must have guessed wrong first time, and hence thought it was encoded incorrectly.

    • Frank

      There is no mistake

  19. Steve H

    Only number 52, did better last week. Wish I’d
    had more time to think about it earlier, but
    work intervened. Must sort out my
    priorities. I can quite easily imagine
    staring at those letters forever and
    getting nowhere, fortunately it came to me.

  20. Drew

    I think I’ve gotten the first and the third down (minus the food)

    I have most of the second one (except for the 4th word)

    And I can’t piece together how a food is formed based on what I’ve gotten so far.

  21. Casper

    Got the three laws, but struggling with method after that this week

  22. Frank

    #54 yum yum! Nice puzzle.

    (To Michael McLaughlin: there is no mistake in the second law.)

  23. Frank

    I’m baffled as to how anybody managed to guess the correct answer without cracking the cipher!

    • Steve H

      Agreed. Last week’s was guessable from the pattern of words, but it would have taken me many days of guessing foodstuffs before alighting on this particular delight.

  24. Sog worldline

    I have all the laws, except the 10th word of last law. is it the last step ?!!
    any hint ?

    • Gerrit Wessendorf

      #58 – found it difficult, too, but I’m glad it didn’t take me 2-3 days again :) Have to catch up with work now – looking forward to the last puzzle!

  25. KM

    Pulling my hair out (what’s left of it) trying to find the way to unscramble these letters.

  26. Graham H

    #57. That was tough. I can’t believe anybody actually guessed the answer because it is so obscure. 1+2=3!

    • nellythetardigrade

      I think the puzzle gives two of the food name letters directly, and the others can be got by trial and error. That might be what they mean by guessing, although it’s probably not really guessing if they are checking the answer. I hope I’m not giving anything away.

    • Neil

      I’ve finally got it with a helpful hint from further down. Now that I know, I’d say it was more like 1-2=3.

  27. John Duffield

    Philip, did you write this?

    If so, could I have a word?

  28. Chris _Switzerland

    Another really tough one. #65. Got there at last. Getting the text was fine, understanding the coding of the first two was ok but getting that last code and the answer seems to have taken ages and ages! Great fun anyway!

  29. Eric

    Easily my favourite so far, and the most satisfying to solve. Got it in 90 minutes, and for the first time managed to avoid the temptation of looking at the comments before completing it!
    I definitely agree that the key to cracking the code (once you have the laws) is to figure out the double (or triple!) letters first.

  30. Neil

    I got the laws “by inspection” and cracked the codes for the first two. I thought I would have the answer in minutes after that, but I’m not any closer.

    I’ve decided that each code letter cannot (unlike in the first two laws) represent the same thing each time it is used in the third law. But now I’m giving up until tomorrow.

  31. Eric

    For those who have solved: is there any relation at all between the food and the rest of the puzzle itself? I couldn’t obviously see any, but perhaps there is another physics in-joke, or easter-egg in the code that I can’t find?

  32. Swathi Rao K

    I assumed that my answer is right. I entered the answer and now I feel it’s half-right. :-(

  33. Clueless

    #76 Now I only need to figure out why …

  34. Old Bob

    #20 Two weeks in a row where slogging through the cryptography was unnecessary to arrive at the answer – strange for GCHQ. Puzzle three: the content of the phrases was entirely irrelevant, this time some very basic analysis starting at the wrong end gives the answer as one of a very small number of possibles (and a slap from teacher for the use of intelligent guesswork). Guessing well’s important in science, so is being lucky. If they lend themselves to these shortcuts, then the puzzles are not well crafted.

    • Steve H

      Don’t really agree that the content of the phrases last week was irrelevant, but difficult to discuss without giving too much away. But vaguely, the source of the phrases gives a clue that the answer will also be a phrase of the same type. And if you look up the source of the the phrases themselves, it tells you which lines to draw in the diagram. You can draw the lines without connecting them to the phrases yes, but then you don’t know which crossing points are the ones to concentrate on.

      • Old Bob

        Yes it was necessary to recognize the phrases and their associations, but you don’t need the text content for that. Easily spotted by pattern on Google. I did decrypt one the long way – that mainly showed that it wasn’t necessary to know the plain text.

      • Steve H

        Can’t seem to reply to your message, so replying to my own. Yes, good point, I did the same – just decoded the simplest phrase then having spotted the rationale, googled for the other phrases rather than more decoding. I actually preferred it that way since I’m a physicist not a cryptologist, so was quicker for me.

  35. Marky V

    When some of you talk about “double coded letters” or even triple, I guess you are referring to the low case letters, right?

    • Steve H

      Actually I think both can be helpful. But for me it wasn’t actually those that gave the game away but something else, they were just a nice confirmation of the idea. For me it was when I started to look at the sequence of undecoded letters in the first phrase that it suddenly clicked.

  36. Leigh

    I’m starting to feel a bit dim sitting staring at these double/triple letters completely failing to work out why they are different. Am I missing something obvious or do I just keep experimenting with codes and rules until I find one that works?

    • Steb

      I was misled by the double and triple letter hint – the repeated letters in the coded text were no help. However, after guessing at the wording of the three laws I found it helpful to look at the double letters in the plaintext and what they encoded to.

  37. TheOldRic

    #88 The third cypher is not strictly reversible.

  38. FoxyV

    #90 That was hard work, but I got there in the end.

  39. Mat W

    Head well and truly done in with this, mainly due to not being able to work out what cipher I’m looking it. Would almost have preferred the full ciphertext!

    Would someone that has solved this, and can identify the cipher, be able to tell me whether it appears on this list:


  40. James

    Can anyone tell me anything about the way the cipher in 1&2 relates to 3? Thanks.

    • Paul

      James – you may find it helpful to think about how the letters represented by “mm” would be encoded using cipher 1, then about how they would be encoded using cipher 2. Then apply Graham H’s hint of 22 Oct @ 8.37.

  41. Mark

    Clueless after almost solving the three lines. need a hint on the 10th word of the third line.

  42. Justin davies

    Just an idea Louise. As the number of solvers reduces week on week, perhaps we can keep going until there is only 1 person who can crack it! Lol.
    I’m kidding, just gutted next week is the last week.
    Thoroughly enjoyable.

  43. Ian

    fun :)
    repeated is not equivalent to adjacent

  44. James

    #99. almost respectable seeing as I have a lot else on. Thanks Paul for tip.. I’m kicking myself.

  45. Drew

    I had ruled out the answer previously as I didn’t consider it a “food” as much as something you ingest.

    I’m still not 100% sure I can back everything up to get there, but i’m done


  46. Gomez


    My favourite puzzle to date – possibly because I found it the easiest so far.

  47. Mark

    Respect to those who solved this, I suck

  48. KM

    I’m confused. After I have the laws do I need to decrypt again to find the food? Please help.

    • Mark

      When you’re decrypting the laws you’ll see the food appear

    • Old Bob

      Its not enough to just work out what the text of the 3 laws is – you need to work out what the encryption algorithm is in each case. Do the first one first…..

  49. Old Bob

    #20 by slight of hand, now #112 by actually solving the cryptograms.

  50. AtR

    Got there eventually – much better than the last one.

  51. Doug

    #114, by breaking the code. I thought it was fun!

  52. Les

    #116 wow-took over 2 days.Good advice from Steve H at 11.12am,Old Bob at 9.44pm and Paul at 4.24pm[inc Graham H] all helped-4 down!

  53. J Millins

    Hate myself so much ^.^ Spent hours looking at it getting nowhere then as soon as I try to get to sleep it comes to me and solved in 5 mins.

  54. Mat W

    I’ve looked at digraphs, trigraphs, tetragrapghs; at Vigenere, Playfair, Four-Square; at periodicty, eccentricity and electricity; I’ve found repeats in plaintext and ciphertext; I have spreadsheets and spreadsheets and paper and paper; and still I have absolutely nothing.

    I therefore think that either I’ve made a mistake somewhere, I have the wrong plaintexts, or I’m making it more complicated than it actually is.

    Any comment on the above, or another hint (obscure if you wish) would be great.

    • Leigh

      Sounds like you’re over complicating it, but I was right there with you with the spreadsheets and paper for 2 days! You don’t need all those things. My correct answer was done on one sheet of paper and no special techniques. The clues others have given are really helpful so I doubt I can add much, though clicked for me when I wrote out the coded and uncoded versions together so I could compare them better.

    • Paul

      Mat – in response to your earlier post, I don’t think that the laws could be rendered fully into ciphertext. Some plaintext is essential in each message in order to decipher the encoded text. (You said you did not mind if the hint was obscure!)

    • Mat W

      Thanks Leigh and Paul – that’s just what I need. I will pull back and recalibrate!

  55. Leigh

    Hallelujah! #121
    That was a tough slog. Got the phrases, then got stuck for a day. Got the first 2 codes yesterday, then stuck all night again. Reread the clues this morning and released I was a muppet and didn’t read one right the first time, and finally twigged on the 3rd code. I do feel like my brain had a good work out though :)

  56. Kumaran

    :) #123
    I wonder how people got the answer by guessing. I worked out the code.

    • Old Bob

      For me there was a strange little back door into the answer that does require all the rest of the text to be known (but they can be guessed), but does not require any knowledge of the encoding/decoding methods. It still took me another day and a half to find the answer ‘properly’ because knowing the answer doesn’t provide any great help with the method. The backdoor must be largely coincidence – but of the 3 most likely answers it offers, one is the correct one.

  57. Steb

    I’m not sure these codes really qualify as such. For example, even those who know the rules may struggle to decode a short message:

    c mpll ajgey giy lxg rfsamfcm wemjdd yyln by b wy banay bwqjoc jbhhe ptaa bbj gvnk stiaqjxmrwd

    • Leigh

      Well to be fair you haven’t exactly coded that message by the same rules as the originals. I would say it’s still a code, just not a cipher.

    • Steb

      I tried to use the same method as code 1, I may have made a mistake however.

      • Leigh

        I don’t doubt your working Steb, and I admire your dedication as I tried coding something and quickly got bored ;). I just think you have to keep some original letters in if you’re following the same rules as the puzzle.

      • Dead or alive

        Steb, if you are encoding using #1, you have to start with at least one CAPITAL (unencoded) letter. Otherwise you have to append your stuff to #1, it cannot stand alone.
        Vice versa for #2!

    • Steb

      That was sort of my point; that you probably need some of the letters to start with. With a long enough message and you could reduce it down to a substitution cipher and solve by the usual methods. Actually, I had unconsciously made an assumption about how the codes would work if there were no letters revealed. I now see that there is some pattern in which letters are revealed in the three codes, such that my assumption is never needed.

  58. Vairat

    Is it possible that us, international solvers, may not be familiar with this food?

  59. Graham W

    #131 – Good one!

  60. Tracey

    No. 132 – finally!!

  61. Clive Thomas

    Finally! And to think I very nearly got it two days ago but put the wrong vowels in, sending me off on all manner of tangents! #134.

  62. KM

    Despite all the hints I am still confused. Must be missing something or maybe I’m just too thick.

    • Old Bob

      Despair not, there comes a point when you’ve got so many jottings and diagrams that you disappear up your own fundament. You don’t need any of it! Throw all the doodles away, start again by writing out (or typing in monospace) the first phrase encrypted with the plaintext below it. Then look along it – that really is all you need. Once you’ve spotted the trick in the first one, the rest follow.

  63. L

    So I guessed the answer, some of the clues together with a good guess led me to it. And I have the three laws. Now I’m trying to figure out the encoding. Started by trying to find out why certain letters are left, the capital letters. And it made sense for the first 9 words of the first law & last 10 of the 2nd, but can’t figure out what happens then and I still can’t find what the letters that get coded get coded into. Are there going to be solutions at the end of the weeks for those of us that couldn’t do it all?

    • sarah

      i would look hard at the coding for the lowercase letters of (only) the first two words in the first law…

      • TheBigBean

        Thanks. This helped a lot. After cracking the first one, the rest fell into place quite easily.

        Didn’t enjoy this one as much, but that might be because it took me ages!

  64. sarah

    lovely. solved it in multiple eureka stages, without reading any comments… i found this one easier than puzzle #4.

    • sarah

      oops! i mean, easier than #3. must be getting late :)

    • Clueless

      Sarah: I am curious how you can have two comments, with the second posted before the first. Have you discovered something much more interesting than the code? By the way, how is the Doctor?

      • sarah

        i solved and posted (earlier post) and then read the comments and offered a hint (later post).

  65. Old Bob

    IF YOU WRITE ggd aHf oqVd aNCqvPmgD LceackS zu fyg dfap gggN BccbAii idCd LehacR WbIff bmc PhcVjOUS vgmaclg kN Aja iwika yeekofb lgfc ub CODkb Fer ingN smrd bdkmha nnn tIcLy kf dflacsq YjU Wqla hka Ao fddhe aHuka FvaDk aPhrn hUc BY offu ce izpIg fcVf vbkackS PAcgc ebeeY dND hqhhO WIdH bbj o q bqq f MmrachG RifPcCvmVeLw Wdgoy dH?

    • Paul

      Bob – I AGREa THgc jS WcilD. A very impressive feat of encoding (I think that in WbIff, tIcLy, izpIg and WIdH it is an uppercase i but in Wqla it is a lowercase L). But should it be vbkacjs?

      • Paul

        vbkacjS. Sorry.

      • Old Bob

        Yes you’re right Paul ‘vbkacjS’! What can I say; It was late, I was tired, alcohol was involved… Good puzzle with a clever coding scheme. Still took a day and a half to break the code after the above weirdness had produced the answer. Mis-led by much analysis, including the perhaps even weirder case of the the ‘E’s in the words ‘THE’

      • Paul

        And I am sure that you noticed, but were too kind to point out, that in my post WcilD should have been WhdlD. I should definitely have waited until the morning and re-checked before posting.

      • Old Bob

        A cryptographic spellchecker! – there’s bound to be someone out there who’ll give it a go.

  66. Mat W

    When I read it out, to paraphrase, I have all the right letters, but not necessarily in the right order. I believe I am on the right track (or closer to it) after the many helpful hints, and have a plausible collection of letters that so nearly make sense, but still it won’t yield. Grrr.

  67. JJGravity

    Good thing I have a job so I have plenty of time to figure this out…
    I’m stumped on the one word in the last law. I obviously have no talent for cryptography – or plent of talent for making this harder than it is.

  68. uszkanni

    I solved this earlier (and tossed my notes) but I’ve been bugged by the penultimate word of the third phrase. Shouldn’t it end with OACHES and not OACHIS?

  69. Rob

    Finally got it. #174 Took a while though…

  70. Clueless

    Sarah: I am curious how you can have two comments, with the second timed before the first. Have you discovered something much more interesting than the code. By the way, how is the Doctor?

  71. Mat W

    Humph. No. 181, but I will put my hands up to having made a semi-intelligent guess. I am however determined to nail this thing the proper way, ideally before stage 5.

    Did anyone else here attempt Simon Singh’s Cipher Challenge when it was out (~10 years ago)? This is bringing back memories!

  72. Darren McLean

    Finally! I will not be defeated. #185

  73. Old Bob

    Ah: you could have written ‘Bob’ differently too – is that too obvious?

    • Old Bob

      Sorry, comment should have gone to Paul

      • Paul

        I agree that writing ‘BOB’ in cipher 1 and cipher 2 would probably give too much away. I hope that others have found the additional source material from the earlier exchange helpful.

  74. Mat W

    Could someone confirm that when I have done as Old Bob suggests (Oct 24, 2013 at 8:33 pm), I should be able to work out a way of solving the first code/cipher without resorting to fiendish anagram solving? (Re my Oct 24, 2013 at 10:29 pm comment)

    • Old Bob

      Hardly my place to confirm it, but it’s true – sarah put it even more succinctly (Oct 24, 2013 at 9:34 pm) – The first two words of the first phrase are enough to crack the general method (and this reduces the clutter to a minimum). I’m afraid the fiendishness is in the simplicity.

      • Mat W

        A ha. Thanks Old Bob (and Sarah). A breakthrough has occurred. That’ll teach me to throw away things I assume I don’t need.

        More to do, but I feel like I’m on the way!

  75. Elias P.

    Finally #193!!
    It took me 4 days this one..

  76. Dead or alive

    Cracked it by analysis, not guessing.
    #1 AND #2 = #3
    Look at when the letters in #1 and #2 are replaced by the code. Work out why.

  77. Andrew W

    #198 worked it out at last! After reading up on cryptography over the last few days only to find I didn’t need it. To quote Old Bob narrowly avoiding “disappear up your own fundament” disease just managed to “KISS” that goodbye. Clever puzzle.

  78. Adam

    Grrrr, I’m sooooo close to solving it… I’ve figured out that the codes for #1 and #2 are very similar (one might say one is “backwards” from the other), but I’ve seen hints saying things like 1+2=3 and getting stuck there.

    • Andrew W

      If you apply either 1 or 2 to 3 it doesn’t work, in what way doesn’t it work? There is the clue.

      • Adam

        From what I’ve figured out, there is a way that 3a+3b=1 – does that seem to be correct?

  79. Vicky G

    #203. Or, in what way can you add 1 and 2?

  80. Andrew W

    Funnily enough 1 is something that 3 cannot equal by applying 1 and 2.
    Take a letter, do what you did for 1, then repeat for 2 and so on.

    • Andrew W

      Sorry that last comment was replying to Adam.

      • Adam

        Maybe I wasn’t clear – I believe I’ve figured something out, but trying to be ambiguous with the clue.

        Let’s take two “random” things with regards to the coding of #3 and call them x and y. Is it that x+y=#1 or x+y=#2?

      • Andrew W

        @Adam Its hard to talk about this without giving the game away buts its more along the lines of x+y (2 random things about #3) as inspired by #1 and #2 where # refers to the statements. When coding/decoding it is obvious when you hit upon the food.

      • Paul

        My hint to Adam about cipher 3 would be (1) to look at the first 5 words of the third message, (2) to think about the letters encoded to “mm” in the second word and (3) to think about what the letter m represents according to the rule used for ciphers 1 and 2.

  81. Malisha

    #201 i formulated three laws (from wikipedia, actually, one of them is almost word for word the same), and then just looked what letters has been encoded in just the third law. from that letters i guessed two anagrams of five letters and the second worked :))

    i guess i want to solve the proper cipher, so i’ll do some more…

    • Old Bob

      Hmm. I think this is the weakness in an otherwise clever puzzle. In effect the encryption method for Phrase 3 greatly constrains the letters which can be used in the answer. I’d be very impressed if someone could use this scheme to insert a word like JERKY into a meaningful phrase about the third law of thermodynamics.

      • Dead or alive

        This is a quick effort, as you are aware, the beginning and ending words are difficult to hide and you have to keep all the required letters ‘together’. ‘Meaningful’ is pushing the description of my effort a bit far…
        (No responsibility accepted for printing errors!)

      • Dead or alive

        Talk about printing errors…!
        I can’t distinguish between capital I and lower case L in my previous comment. It may be a font thing, anyway look out!

      • Old Bob

        If I had a hat it definitely would be off to you. Not sure I understand the ‘DlY’ but I’m no physicist.

      • Old Bob

        Ah – that explains that

  82. TheOldRic

    I am curious about the demographic of those tackling the puzzles. I am British and was a Member of the IoP when I retired. What about the rest of you?

    • Old Bob

      Oh, go then, I’ll chip in for the oldies. British, living in France, ex-metallurgist (is there any other kind?). Started out at the magnificent and now defunct Fulmer Research Institute – wholly, distantly and somewhat distainfully owned by the IoP. Ploughing own wobbly furrow for the last 25 years.

    • Andrew W

      British too, dabbles as a software developer who likes problem solving. Until the BBC ran a story on these puzzles had never heard of the IOP or Physics World. Scientific training finished at A level. Never really looked at any of the crypto stuff before so surprised to have reached this far.

    • Mat W

      British, in Scotland. Have a physics degree and working in physics but not as a physicist (if you can’t be cryptic here where can you be?).

      Love puzzles, ciphers and codes, although you wouldn’t think it from my shocking performance here!

    • Dead or alive

      Aussie expat in Germany, Bsc(Physics) BE(Elect).
      Grew up reading Martin Gardner, Mathematical Puzzles and Diversions etc. Puzzle fans here would like the card game “Eleusis” in his second book. The game’s inventor Robert Abbott has a
      (I have no connection.)

    • Paul

      I’m British, living in England, A-level physics, lawyer. Came to these puzzles through the BBC website. Loving them.

    • Leigh

      British here too. I’m just an administrator, no physics background. My degree is in psychology. I just really like puzzles. Logic puzzles are my usual thing so #2 was easy for me, but all this code breaking is hard work :).

  83. Ezekiel Romero

    #208. Tough one!

  84. JJGravity


  85. JJGravity

    I live in Colorado, USA. Amatuer Astronomer and not employed in any physics-related field. Just enjoy reading about physics (especially when I should be working).

  86. L

    Argh! This one’s getting to me. Feel like I should have solved it with all the clues, but nothing (I guessed the answer now trying to work it through). Can I check the fact I see a pattern for which letters are coded and which aren’t for the first 9 words of first law (and actually starting for the end in the second) but then this disappears. Am I just looking at a spurious thing I should ignore or am I onto something? And I am looking intensely at KEPLcRS FIddT like someone suggested but I’m just getting a headache. I can’t even see what kind of coding was used…

    • Andrew W

      Take those two words both in their encoded and decoded form and write one below the other aligning the letters. Then ask yourself how would I encode this.
      To un-clutter my mind I took some scrap paper and (I kid you not) a red crayon to write out the above. The mental barrier fell away. Previously used spreadsheets and wrote software snippets all to no avail.

    • Old Bob

      Difficult to say without more info from you and possibly completely giving game away, but: I suspect you have the pattern perfectly but are becoming confused because you don’t yet know how the coding works – and therefore why, from time to time it has to do a slight reset. Ignore for the moment the problem with the 10th word, pretend it didn’t happen and just carry on past it with your theory about why only some letters are encrypted. If you’re right it should just kick back in (with occasional hiccups). When you spot why the hiccups occur you will have solved the encoding.

      • Cryptophiliac

        interesting….how come after the ‘slight reset’ the nice pattern seems to disappear and replaced by something more random?

  87. Mat W

    … and relax. Finally got it the proper way. Oddly, after spending days on this, it was much easier than I thought. Thanks to all who provided hints and brought me back from two wrong paths.

  88. Dec McG

    #218, but by reference to rule 3 only. Whether I will break the code correctly or not is a whole other ball game.

  89. David

    #229 still a small number of entries four days after the opening. I suppose I have to thank Malisha and the Italians!

  90. Adam

    EUREKA! #231 – While the code of line #3 doesn’t have MUCH to do with the coding of other two lines, it was extremely helpful for me to create a chart (or spreadsheet) showing the coding for each lowercase letter for line 1, line 2, and line 3 side-by-side-by-side. Only by doing this was I able to see how the coding for line 3 took shape.

  91. Dartmoor Graham

    I’ve been away this week without Internet access so only started this morning. Was #238. The answer was certainly weird and I can’t imagine how anybody could guess it! Looking forward to puzzle 5.

    • Adam

      I thought the same thing, Dartmoor – I can’t imagine how anyone just guessed it out of thin air.

  92. Elias P.

    ALldffGh j FnUtl iee jIPueR qd ddiidd pce euohqc cHE ndg hoWS i CoUkfdm ojcv bv wLGgglffM Fjg cch suiRf hci oog g sOnVmh oh BY Hcno de fffmi I pdARNfD TO USa cXCEL :) Nice puzzle!

    • Dead or alive

      Using #3:
      ALTHOUGl I FtUND umE CIPzjR zr pismmh Awi ixxqvh tHE qWo LAWS I CvUswyT FsgD qy yLGvRvsHM Fqn iiE vxuRD ryq Arm p SOLVvo vT BY HqNw gm tsjSn I viARNjD TO USg dXCEL

  93. Greysquirrel

    Success #248! Definitely guilty of over-thinking this to begin with. Moving from the computer to paper and pen definitely helped.

  94. Doubledodge

    Been hammering away at this one all week. Decided to give up and wait for the solution to be revealed at some point. Unless, that is someone feels like telling me why in #3 mm translates in several ways to the decrypted letters but there is no way the letters jj can match the decrypted letter sequence it needs! Or have I got the phrase wrong? Somebody?

    • Ezekiel Romero


      I assumed you have decoded #1 and #2. Then, as stated by someone earlier, “#1 + #2 = #3”.

      Hint: It Cuts Both Ways

    • Old Bob

      Brilliant – system clock on IoP computer didn’t change last night, so I’m not allowed to reply for an hour.

    • Old Bob

      As Ezekiel Romero asked, have you fully solved the encoding methods of #1 and #2? If so, the method in #3 is intimately related to those (not sure the arithmetic representation helps much in visualizing what’s going on – but it is true). Decoding in #3 is not as reliable as #1 and #2 and it is ‘mm’ that shows that most clearly.

    • Dead or alive

      Try these.. #1 #2 #3
      NEVbR ODa ce gibm
      mbige caD OR bVEN

    • Paul

      Doubledodge – As you say, “mm” ‘translates’ in three ways. You may find it helpful to think about the ‘relationship’ between (some of) those three ways, whilst bearing in mind what m represents according to the rule in ciphers 1 and 2. As Old Bob says, “jj” works fine. Do not be misled by the fact that it is a pair: in this respect, it works in a different way from “mm” (but still according to the rule for cipher 3).

      • Paul

        Another – perhaps more helpful – way of making the last comment would be to say that the fact that ‘mm’ translates as a sequence is a coincidence.

      • Cryptophiliac

        can one take it that there is a method to the madness with regard to the additional ‘random variable’ in 3?

  95. Old Bob

    Doesn’t sound like you’ve got the #3 coding scheme quite right. jj works fine.

  96. nsw

    At last! #254 took ages to get the coding for the last law! If you didn’t know the plain text for #3 is it always possible to decode it? My scheme does not seem to be…so not sure if I have it 100% correct.

  97. Adrian B

    #266 – and still a few hours of the weekend left….

  98. Andrew Wright

    #270 – that took far too long!

  99. Dr X

    One thing to note is that the third code is not as well defined as the first two. Once you understand the first two, it gives you the idea for the third one. But the third one can be encoded, but can’t really be decoded. In the sense that there are sometimes multiple legitimate decodings. The mm for example have an obvious decoding, but there are two more decodings for each letter than would also be correct. So taking the known plain text and figuring out the encoding may be the easier way to figure out the system.

    Another clue I will offer is to consider which part of each of the three phrases is in plain text.

  100. Errol

    Re: decoding #3

    There may be more than one legitimate decodings, but I think the idea is to choose the one that makes sense. [Now, I’m confused:)]

  101. Dartmoor Graham

    Ah yes, there are ambiguities with the mm (for example). But the answer can be derived without using its own lower case letters and hence there are no ambiguities. These letters serve only to verify the result and you do not have to choose one that makes sense.

  102. Rivet N

    #263 yesterday.
    A brilliant coding scheme!

  103. Jamie

    2 days of my life gone but it feels good to get it done. in response to demographic, i’m a physics undergraduate, britain.
    And a hint for anyone stuck, try to work out the logic behind the puzzle thoroughly before diving right in, it has a strict set of rules which (once found) make the game alot easier

  104. Dan

    #280. Taken all week.

  105. John

    Bloody hell that was a complicated one … my head is hurting but I finally got it. I’m not sure how I got the cyphers … one second I’m not seeing any pattern then all of a sudden I see it

  106. Jesse

    #282. A bloody complicated one, esp for a social scientist :)

  107. Martin Kimber

    Nice! (As long as nut-free)

  108. blackshadow

    #283. Tough, 3 goes at it.
    Bring on tomorrow.

  109. Chris

    Hi Folks, I havent had as much time this week to try and solve this one, but i have the first two done. But i cannot see the connection. Any help/hints or even just the answer at this point would be appreciated. thanks in advance. I want a clear head for the next one. :)

    • Doubledodge

      I also had to admit defeat and want to clear my mind for puzzle 5 now so as Chris asked. A clear explanation (no hint helped me so far) of rule 3 with how it works for jj would be gratefully appreciated – BUT could you email it to the public email address of so any of us who are now ready to give up can all privately read it over at without having to plead embarrassingly in public like Chris and I :-)

    • Doubledodge

      Heartfelt thanks to Dan for the further hint and also to the “Hoki-Koki enthusiast” for spelling it all out step by step. I am certainly not kicking myself though I am certainly in awe at anyone who got that third rule on their own. Well done all of you.

  110. Lorax

    and puzzle 5 is the most difficult ???

  111. Michael McLaughlin

    #340. Left it alone for a while. Those clues about #1+#2=#3 will put you off. I can’t see it.

    • Andrew W

      Michael, to get to the logic look at the double letters in the plaintext that you decoded. What pairs do they match in the encoded phrases of statements 1 and 2. There are three pairings in all and you can work out several things from those letters and also what was not encoded (McaS).

      Also do not get hung up on the ‘mm’ as you do not really need it. Go from plain text doubles to encoded pairs not the other way around.

      Sarah’s comment on Oct 24, 2013 at 9:34 pm is good advice. Those first two words are all you need to reveal the general logic involved, it is just applied differently in each statement. (I over worked this puzzle and had to write out those two words on paper along with their encoding).

      Hopefully you will see what the #1+#2=#3 clues were driving at.

    • Dan

      Michael, once you’ve worked out the encoding for #1 and #2, use each of them to encode the plain-text of #3. (Use some kind of placeholder for the characters that won’t encode because the plain-text is still unknown.)

      Then try applying the #1+#2 rule and you should find that #3 emerges, except for those placeholders. You should then be able to infer the missing encoded characters and from them work out the plain-text missing word.

  112. Nolene

    I have the laws, but can’t seem to break the cipher. The upper and lower case letters are throwing me off.


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