The Odd One Out

I am strongly opposed to questions of the type “which is the odd one out” during IQ tests. On the other hand, I do not mind them in different settings, especially when they are fun. Inspired by Martin Gardner, I spent a lot of time drawing this picture, and now I have to share it with the world. So, which is the odd one out?

Odd One Out



  1. misha:

    The one that says “I am special.”

  2. Mary:

    No, it is the one that says “I am not special.”

    The second one says “I am special–I am the only one without a frame.”

    The third one says “I am special–I am the only one that is not square.”

    The fourth one says “I am special–I am the only one that is not red.”

    The fifth one says “I am special–I am the only that is small.”

    So it must be the first one, because it can’t say that it has any special attribute not shared by at least one other object in the array.

  3. Lev:

    The first oddly normal.

  4. misha:

    Hmmm, you are probably right. My first remark was just a joke, but it had some anti-truth in it.

  5. Austin:

    This is adorable!

  6. Scott Carnahan:

    This puzzle made me chuckle. I like it.

    I saw a lot of IQ and pattern-recognition tests when I was young, and it became clear that they were essentially tests of how well you could play their game, i.e., it really helped if you could distill the exam writers’ prejudices from the questions that were asked. As far as I can tell, scoring well on these exams is more a question of practice and cultural osmosis than any sort of innate ability.

  7. Qiaochu Yuan:

    Scott, that’s an interesting way to phrase it. I would argue that “playing their game” is itself a testable ability that varies from person to person and that in my experience it does have some correlation with what many people would call “intelligence.” Some people understand the rules quickly and others don’t.

  8. Øistein:

    I think the first one is special too, since it’s the only one that isn’t special. You can vaguely hear it whispering “I want to be special too…”

  9. Sue VanHattum:

    Here’s an interesting look at IQ tests as cultural attunement, rather than something innate:

    I like your question, too.

  10. Simon Hawkin:

    Either one. A good example!

    Disclaimer: I am not opposed to those kinds of iq questions, but I am doing poorly with them.

  11. Jack:

    The first thing that hit me when looking at those is the big border.. so I’d say the odd one is the second because it is border-free. But I guess the green versus red variable might be a good choice too.. anyhow, nice one : )

  12. Shitcock:

    The odd one out is the first one.

  13. molly bloom:

    by deduction – every single one is odd, but the leftmost is the oddest – has similarities with all of the others, which none can claim

  14. Uri Schonfeld:

    Very nice. First one :)? It reminds me of the “life of brian” scene “we’re all individuals”

  15. random_nutter:

    This one is somewhat ambiguous and open to interpretation. If I had to pick one, I’d go with the circle, since it’s the only one with an odd number of edges. ;p

  16. cak:

    Nice point scott, for example it is incredibly important to distill the writers bias from the seeminly simple question: 5+5. I mean, anybody can go for the obvious choice, but when you look into it, when you really look deep down into the soul of the question, you discover the truth. Why 5? What do we have 5 off, well quite obviously we have 5 fingers and thumbs, and the writer is obviously biased against people born without all 10 digits, or having lost one.

    So the answer is hand clap.

  17. jan:

    the first one, cause it’s not odd.
    love the approach to the old idea.

  18. LOOF:

    The circle

  19. Not Anonymous:

    I’ve used something similar in interviewing applicants: I draw a red circle and a blue square next to each other; then I draw a blue square, and ask which of the first two figures is most similar to the third figure.

    The correct answer, of course, is “it depends whether shape or color is more important”.

  20. Not Anonymous:

    Sorry; the second “blue square” above should of course be “blue circle”.

  21. Yo Tater:

    I think everyone here is over thinking it. The odd one out has to be the 4th one, because it’s GREEN. Think about it, all of them are red except for the green one. It’s tempting to think that there’s more to this question, but just think of 5 people wearing shirts of which 4 are red shirts and 1 is a green shirt. Given this, the odd one out would be the green shirt.

  22. Tim Osin:

    Ochen’ ostroumno! Very clever!

  23. heuristic:

    The example is a strawman, contrived to try to prove a point. Test questions are unlikely to be so ambiguous.

  24. billswift:

    It also depends on whether they’re color-blind.

  25. Tam:

    The first one is the odd one out, as it is the one that has most in common with all other items.

    Each object has four “essential” properties:

    a) Base Colour (red or green)
    b) Size (small or large)
    c) Bordered (yes or no)
    d) Shape (square or circle)

    The first object has 3 of the 4 properties in common with each of the other objects.

    In the set of other objects, each object has only 2 of the 4 properties in common with the other members of the set.

  26. Scott Carnahan:

    I guess I should have made my points more clearly. When I used the word “prejudice” I meant that a person who writes IQ tests has some not-necessarily-well-founded internal idea of what intelligence is, and how some model intelligent person would answer a given question. This does not necessarily mean that the writer intends to discriminate against a specific population, but it may reveal cultural biases. For example, in the article that Sue VanHattum linked, there was some discussion of grouping everyday objects based on abstract classification (favored by IQ testers) versus functional relationships (favored by people who work with said objects). If you don’t have a priori knowledge that abstraction is valued by testers, you will probably score poorly on such a test.

    Abstract IQ tests tend to rely on a rather limited library of tricks, so people who are exposed to them when growing up have a strong advantage. For example, if you didn’t know that many IQ testers like to interlace simple sequences to make them look harder, you’d have to think a lot more before recognizing a pattern. Some people can recognize this fact on the fly, but a) the test doesn’t distinguished them from people who were warned about it ahead of time, and b) this sort of recognition can be trained.

    Certainly, there are congenital obstructions to picking up these tricks, but one needs to be very careful when accepting bold claims about the predictive power of IQ. The psychometrics literature is riddled with statistical malpractice, and fairly rotten with a eugenics agenda.

    Another review of Flynn’s work – I especially like the mention of the Perron-Frobenius theorem.

  27. theris:

    the first one is, because it has more than one feature other have. it’s red, square, big and outlined.

  28. theris:

    so basically it has 4 properties, not 3, tam 🙂

  29. Scott Carnahan:

    Ugh, grammar fail. Let’s try the second paragraph again:

    Abstract IQ tests tend to rely on a rather limited library of tricks, so people who are exposed to those tricks when growing up have a strong advantage. For example, if you didn’t know that many IQ testers like to interlace simple sequences to make them look harder, you’d have to think a lot more before recognizing a pattern. Some people can recognize the tendency to interlace on the fly, but a) the test doesn’t distinguish those people from people who were warned about the pattern ahead of time, and b) this sort of pattern recognition can be trained by drilling.

  30. Peter Huesken:

    The fist one is special, for two reasons:
    1) as stated by Øistein: it´s the only one that isn´t special
    2) the first one differs from the other four symbols in exactly 1 way; the other symbols differ from each other in 2 ways.

  31. Chris Chang:

    Correlation does not prove causation, but it does demand explanation.

    I certainly agree with Scott that IQ tests are vulnerable to practice effects. When I hear about an individual scoring 180 on an IQ test, or a large group of kids in a test-obsessed culture averaging 140, I consider it extremely unlikely that the individuals in question can be expected to achieve at a level at least 5 or 2.5 SDs respectively above the mean under any metric I care about. And I am perfectly aware of how much of an advantage my math contest background still gives me whenever I look at a quantitative problem intended for an IQ-like test.

    That said,

    – it is important to not use these limitations of the instrument as an excuse to dismiss it altogether. Suppose that one source of IQ tests’ predictive value is that there are snowballing benefits in modern life to picking up some subset of the “limited library of tricks” early. We would clearly want to discover this, and then modify our educational system to effectively teach those tricks to as many children as possible. This is impossible as long as rigorous thinking about IQ is confined to the political fringe.

    – I’m not sure it is fair to characterize the modern eugenics agenda (as opposed to the ’40s “kill or sterilize the untermensch” one) as rotten. Yes, there are still a few bad apples among its supporters. However, given the rapid advances in genomics and related technologies in recent years, it is not unreasonable to look ahead to the day where selection for, or even engineering of, particular traits in embyros is practical for many. This ability allows many eugenic goals to be achieved without any of the aggression or coercion that gave traditional eugenics a deservedly bad reputation.

    I oppose any power that would coerce me to use such technology to have kids to their specifications. But I oppose, equally strongly, he who would deny me the right to use such technology at all.

  32. Chris Chang:

    The example is a strawman, contrived to try to prove a point. Test questions are unlikely to be so ambiguous.

    “Ambiguous” is not a criticism I would make of this test question. (“Clever” and “cute” are, on the other hand, appropriate adjectives.) Nobody has made a serious case for a Schelling point other than the leftmost object.

  33. Nikolay:

    It is nice!
    I offer to expand the collection with a red framed 3d cube 🙂
    BTW, what Gardner’s task did you mean?

  34. Peter Huesken:

    @Chris Chang Correct. No ambiguity at play here 🙂

  35. misha:

    To Chris Chang:
    you wrote:”Suppose that one source of IQ tests’ predictive value is that there are snowballing benefits in modern life to picking up some subset of the “limited library of tricks” early. We would clearly want to discover this, and then modify our educational system to effectively teach those tricks to as many children as possible”

    What would be the purpose of that? So these children would just do better on that particular test? Any other purpose? Isn’t it easier to modify the test rather than the educational system?

  36. misha:

    Is the purpose of the educational system to prepare people to pass the tests?

  37. Maria Roginskaya:

    The odd one is the number six, because it is invisible 🙂

  38. Chris Chang:


    Reread the first quoted sentence carefully.

    I was referring to the correlations between mid-childhood IQ test scores and a wide variety of metrics of adult success. In principle, it is possible that this correlation has nothing to do with the tested skills — privileged upbringings might confer those skills while increasing the chance for adult success via a totally different causal pathway. However, if that were the case, it should be simple to construct a “privilege test” quite different in character from an IQ test, and such a privilege test should have greater predictive value than the IQ test.

    Since nothing of the sort has happened, the possibility must be considered that other factors are partly responsible for IQ’s predictive value. One possibility is genetics; I am actually okay with limiting discussion of it until the day, hopefully coming soon, when we can do something positive about it (rather than using the claim to argue for large-scale sterilization incentives and worse, as the politically tone-deaf are wont to do). A more immediately actionable possibility is that at least one of the skills directly affects learning ability. Learning the alphabet may be a rote memorization task, but nobody will dispute that if you don’t do it early in life, you’ll be at a serious disadvantage. Perhaps that is also now true of one or more teachable pattern-recognition habits.

  39. misha:

    To Chris Chang: Just float the idea of the privilege test to you local legislator and see what happens.

  40. Chuck Turnitsa:

    This seems obvious. There are four attributes – size, shape, color, border. The first one is unique, because it is the only one that shares 3 attributes (in each case a unique set of three separate attributes) with each one of the other objects.

  41. colorblind:

    There’s a green one? Oh, that changes everything.

  42. Max:

    Have to go w. Chuck on this. Though in my topsy-turvy brain it stands out in not standing out.

  43. Raul Carrillo Garrido aka metsuke:

    I think the one that odd out is the observer, it’s the only that doesn’t present any characteristic of the five object shown. So the odd one i’ts ME (the person who reads and try to solve the question)

  44. JarFil:

    Intelligence is the fastest achievement of the simplest correct answer, not te ability to come up with the most lenghty and complicated one.
    The simplest answer is: color difference is perceived before form or property set evaluation.

    The odd one is the green one, Occam’s razor.

  45. Carola:

    I agree with the last comment.

    The problem has got no solution, it has multiple solutions that the person who is asking will evaluate to know you, and know how do you think, what prejudices do you have, what would you do in some situations.

    A lot pf people think the first one is “the one” but I believe this is due left-to-right writing. If they were used to read right-to-left direction, maybe they would think the “last” one is the one off. Many people think four figures are equal… depending on the fifth one! So no figure can be the one off as all of the pieces need that one to “make sense” together.

    To me, it is clear that this problem has got no solution; you answer will make you fit in any category stablished by the one who’s asking.

  46. Louis B. Cypher:

    None. Why should any of them be left out?

  47. Rober:

    Hola, yo creo que no sobra ninguno, que sobran todos, que falta alguno…Esta prueba depende del observador y su subconsciente, a primera vista, cada persona se fijara segun una caracteristica propia que le sea relevante instintivamente, es decir. Una persona racista dira el verde, una persona con complejo de inferioridad dira el pequeño, alguien que se sienta aislado, diferente dire el circulo, etc etc.

  48. Capt. Obvious:

    It’s obvious. The second one is the only one without a frame.

  49. David:

    My solution:

  50. Noam GR:

    Hey, this was neat, worth sharing 🙂 I linked to this puzzle and your blog on my post today.

  51. juanba:

    Let’s take the object’s properties for the set:

    Object P1 P2 P3 P4
    1 red square framed big
    2 red square not-framed big
    3 red not-square framed big
    4 not-red square framed big
    5 red square framed not-big

    let’s assign a one code to the positive property and a zero to its composite value
    Object encoded-value
    1 1111
    2 1101
    3 1011
    4 0111
    5 1110

    We can see the zero value moving from the right to left so the sequence of objects follow a negative-property shifting from the right side to the left.

    The best candidate to be out is the first object because it breaks above sequence, obviously due to it hasn’t any positive property

  52. fscliment:

    There is no one odd out. All are similar and differents, like the human being…

  53. Tracey:

    As a degreed math major, I find this amusing. I was able to pick three possible “one of these things is not like the others” at first glance. Then is the decision on which ‘odd’ one out the questionnaire would like to hear about. HA HA. This seems more like a personality test question than a true IQ test question since there are many ‘correct’ answers. Or maybe it’s more of a proof question. Pick the odd one out and then explain.

  54. Carnival of Mathematics #59 « The Number Warrior:

    […] At Tanya Khovanova’s blog, be sure to try what I believe to be the best “odd one out” puzzle ever written. […]

  55. Tanya Khovanova’s Math Blog » Blog Archive » No Odd One Out:

    […] recent blog puzzle where my readers had to choose the odd one out became extremely popular and was republished in many blogs around the world. Some commentators […]

  56. Karen J:

    It is obviously the first one, red square with border, because it is the only one that has no unique properties. Each of the others, 1 no border, 1 circle, 1 green, and 1 small, is unique in one way

  57. James H.:

    My thought process was that the first object has three things in common with ALL the other objects. That cannot be said of the other objects.

    I like reading how other people thought about the problem in a different way to get the same answer. I like Karen J’s explanation.

  58. Evening Bud:

    I think second one is different just because it has no borders and no bounds to limit itself. But still can be one among the array.

  59. One of these things is not like the others… « The Math Less Traveled:

    […] Hat tip to Tanya Khovanova. […]

  60. ATOzTOA:

    Great one… I haven’t really thought about the idea of being the odd one, by not being not add at all… 🙂

  61. A not so obvious puzzle « Newton Excel Bach, not (just) an Excel Blog:

    […] A not so obvious puzzle Posted on November 26, 2009 by dougaj4 A nice puzzle from Tanya Khovanova’s Math Blog […]

  62. Will:

    The prevailing opinion is that the first is least unique and is therefore the oddest. But it is the mean and the others are one deviation from it. Can the mean be the statistical anomaly? Is that what the question asks for?
    It seems odd, if not contradictory, to hold the least odd as the oddest. Measuring the meta-“how well it fits in”-attribute shouldn’t then influence that measurement itself.

  63. cedric lazlo:

    @Will: yes, i think the mean can be a statistical anomaly. the average person has roughly 1 testicle and 1 ovary. but a person with these characteristics would certainly be an anomaly.

  64. João Azevedo:

    It’s the second because it’s the only with one color

  65. Tanya Khovanova’s Math Blog » Blog Archive » It Has Been Two Years:

    […] The Odd One Out […]

  66. jean valpoullion:

    well, i also believe it is difficult to answer this one. intuitively i would also say: the second one. in this case i do not agree that colour is detected before shape, as the black frame makes the biggest impression, and the other differences only come with giving it thought . and to the ‘the first one’ discussuion: what if another of the objects was the first one? would the others be set into realtion with this new first one? is it perhaps natural, to watch a row of objects in relation to the first (?and most important?)one? smiles4miles.

  67. William Woods:

    It’s interesting to look at this example in the light of the referenced Flynn / Gellner theories. While there is an undeniable mathematical argument for the first one, this is clearly an abstract “High Culture” answer, and it is not visually salient. That’s what makes it a fun puzzle. On the other hand, from the perspective of cognitive perception, to me and at least several of your commentators, the strong black borders are visually salient and the absence of this on the second item makes that one jump out as an obvious preference over the cases that would be justified by odd shape or color, which in turn are both more salient than the absence of uniqueness. Theoretical claims of color dominance over shape and abstract set inclusion don’t seem to apply to this very striking attribute (perhaps because the black border is not abstract). It would be interesting to see the effect if the borders were thin lines instead of the strong bold frames that they are. Also, there may be individual differences or priming differences in the preference of the color cue versus the border cue. As with certain optical illusions, I can think myself into the state of seeing either one or the other as dominant.

  68. Tanya Khovanova’s Math Blog » Blog Archive » The Odder One Out:

    […] My recent entry, where I asked you to choose the odd one out among these images […]

  69. Ben Boxer:

    The first one is odd, because it is the only shape which cannot appear in a subgroup by itself.

    Main groups are;
    The set of shapes which are square
    The set of shapes which have boarders
    The set of big shapes
    The set of red shapes

    subgroups are;
    The set of shapes without boarders
    The set of shapes which are not red
    The set of shapes which are not big
    The set of shapes which are not square

    Maybe there are no “main” and “sub” groups, they’re all just groups and every shape, except the first one, can appear in exactly two groups.

  70. Wiskundemeisjes » Blog Archive » Welke hoort er niet bij?:

    […] goed na voor je antwoord geeft! Hier vind je de oorspronkelijke puzzel van Tanya en hier staat haar analyse van de reacties die ze […]

  71. W.A. ten Brink:

    They’re all the odd ones. And because of that, they all fit together. % is smaller than the others, 4 is green, 3 is round, 2 has no frame and 1 is the only one where every feature is available in three other figures. (3 others are red, 3 others are square, three others have frames, three others are the same size.)

    But when reconsidering that last point, I can say that 2, 3, 4 and 5 each have an unique feature. The first one has no unique features. Thus 1 is the odd one.

  72. HolyJuan:

    The large white triangle with the white border is the odd one out.

  73. chris:


  74. IQ Test: Which is the odd one out? « blog.karma23:

    […] via Tanya Khovanova’s Math Blog […]

  75. mark p.s.2:


  76. Narwhal 2:

    There isn’t an odd one out. Each of them has a unique feature that makes them unique. The first one is unique in that it is not special, which makes it special; all the others differ from it. If all five are unique and none are identical, none are special, or all are.

  77. Ivona:

    When looking for the odd one out in a series of objects, we need to concentrate on the primary feature that characterizes them and distinguishes them from or likens them to each other.The primary difference between the objects is the presence or lack of a frame. The only object that doesn’t have such a frame is the 2nd one. Therefore, the 2nd object (from left) is the odd one out.

  78. sympath:

    This discussion is a fantastic illustration of varying analytical intelligence and its measurability. The type of intelligence being measured by a question like this is the ability to see all the characteristics simultaneously, see all the patterns, and discern that there is a pattern in the patterns. With that level of intelligence, it’s actually a rather simple puzzle, and completely unambiguous. If you see color initially, (OR the shape OR the black boxes OR the size), or try to take it all in and your “gut instinct” makes you “feel” that one is most different, you aren’t using (or don’t have) the level/type of intelligence being asked for. A logical approach requires you to gather all the information and make complete sense of all the information. If you don’t do that–If you see the different characteristics, but privilege one (like color) over the others, when there’s nothing in the puzzle to indicate you should–you’ve given up on logic and haven’t used the intelligence the question requires. It may well be that even after reading the right answer, which has been explained several different valid ways, you don’t understand, or you don’t feel like it’s more correct than your answer, or you’re certain that there is no correct answer. Unfortunately, this really means that you don’t have the intelligence being measured. Yes, it’s a game. The rule is you have to use as complex thinking as required to arrive at an unambiguous answer. The ability to win that game is one sort of very useful intelligence. This question is very well designed, much better than the ones Tanya describes in the post against this type of question. Perhaps she should be writing intelligence tests!

  79. nick:

    obviously, the one without a frame 🙂

  80. Pat:

    The first one is the only one that shares exactly two of he three characteristics with the others. The others only share one characteristic with each other.

  81. alex:

    they are all weird

  82. Oscar:

    i like the puzzle because it demonstrates how something apparently ordinary can be extraordinary just because all the rest is extraordinary; imho it qed’s the dutch saying “doe maar gewoon dan doe je al gek genoeg” (better behave ordinarily since that is suffuciently weird) – the first one therefore, because it doesn’t stand out in any particular visual way, as do all the others which each have one unique visual property. the first one is the only one that is without anything visually weird and unique: it is not without the dark edge (unique to nr 2) not a circle (unique to nr 3) not green (unique to nr 4) nor small (unique to nr 5). therefore, “not standing out as visually unique” just happens to be a unique property in this context. furthermore, since this property is not shared, nr 1 stands out by a relational, contextual, property and in this it is unique, and the other four have no other non visual property can compete with it.

    ps- also it does remind me a bit of the complex process of determining the result of a cricket game, where the result can be a win, a tie, a draw, no result, or even awarded by the umpires.

  83. Herbert:

    I’m arguing from a completely rhetorical viewpoint. I feel that this is an argument from semantics, particularly in YOUR definition of the word “odd”. If your definition differs from mine, and you never explain what “odd” means, any of them can be correct:

    1: Odd, due to the fact that none of its characteristics are shared.
    2: Odd, due to the fact that it has no border.
    3: Odd, due to the fact that it’s a circle.
    4: Odd, due to the fact that it’s green.
    5: Odd, due to the fact that it’s the smallest shape and is the only one that can completely fit inside all the other shapes.

    5 is my preferred answer.

    This is exactly why I hate those stupid “Impossible Quiz; 98.7% fail this quiz!” and they ask you to click on the smallest button. While most are drawn to the three buttons shown, a supposed 1.3% are drawn to the period at the bottom of the exclamation point. I, personally, would not consider that a button, but a dot. Am I wrong for thinking this? In the eyes of the ad-holders, I would be. But there’s no reason to assume a mere red circle is a button, when the other three are buttons because they have the appearance that if you push it, the upper portion will go down and most likely activate something.

    See what I mean?

  84. quinosonic:

    cool stuff… i’m linkin’ it to my blog right now!

  85. Arthur:

    The answer to the question is probably more philosophical than anything else.

    One could argue that the first indeed is the only one that shares all of its features with one of the others.
    However that makes it unique in itself, so it becomes a question where there is no right or wrong, just opinion.
    The answers are much more interesting than the question itself. The one that claims that others are overthinking it
    because they don’t see it their way is overly confident.

    My answer would be that the question was not designed to have a single answer,
    just a point of view and how that vision is shared.


  86. Arthur:

    An even more interesting question:

    Which one is not the odd one out?

  87. Lisa:

    The first one has no unique features, thus it’s the odd one. Not having unique features is NOT an unique feature, thus all others are the norm. And the norm is that it needs to have a feature that cannot be fount in any of the other figures.

  88. Eirik:

    It’s a trick question. In fact, it’s so much of a trick question he answered it before he asked.

    All of them are the odd ones, obviously.

  89. Drew:

    That was brilliant. Enjoyed figuring it out without hints. That sort of question would ruin a test badly though :D.

  90. Javier:

    This highlights an interesting difference in human minds. To me (what some might term a “left brain” thinker) the answer is unequivocal. It is obviously the first object. That is so clear to me that I wouldn’t even call it a puzzle. It is just a matter of reading the language, and I assume that anyone that disagrees simply doesn’t know this particular language. I happen to be atheist and have similar certainty about the non-existence of deities — there’s simply no question in my mind. And yet, when it comes to ordering dinner or deciding what to wear in the morning, I am often clueless. I hate making those decisions and feel like I just don’t understand that language.

    In scanning some of the other comments, it is intriguing how some people are convinced that the answer is the borderless, round, or green shape, or better yet, argue that there is no one right answer. I am amazed by the confidently subjective, “right brain” approach they take. I imagine most are comfortable being agnostic or mildly religious, and have no problem expressing their culinary or sartorial preferences. While I am confident in my ability to discern logic, I am awed by their ability to thrive in a world of ambiguity and opinion. I am glad our species is capable of such diversity and hope we always have the mutual respect to happily coexist. This, however, may depend on our wise leaders possessing BOTH abilities.

  91. In-between trains:

    Working memory is emerging as the best indicator of fluid-intelligence. This property is slowly removing the need for certain types of IQ tests (depending on that they measure).

    TITLE: The Relationships of Working Memory, Secondary Memory, and General Fluid Intelligence: Working Memory Is Special


    In-between trains.

    What is in-between trains?

  92. Mike:

    Has to be 1 in my opinion since they are obviously all different to each other, it shares the most features with the others while the others only share the same number of features.

    This is figured by comparing size/frame/colour/shape, I’ve closed what I was using to tally but it’s about 10(Answer1):7(Answer2-5).

    I’m like the right-brained people Javier describes but I do know how to work out the left-side like he could work the right if needed.

  93. Farkli olan… « Huzursuz Zihnim:

    […] once nette karsilastigim bir soru ile baslayayim bu gunce projesine. IQ testlerindeki “Farkli olani […]

  94. One of these things is not like the others… | The Math Less Traveled:

    […] tip to Tanya Khovanova. 39.953605 -75.213937 This entry was posted in pattern and tagged odd one out, puzzle. Bookmark […]

  95. Vijesh:

    The term “Odd” is a relative and is associated with a certain reference. The question says “So, which is the odd one out?”. It doesnt specify the exact property with respect to which the oddity needs to be found.
    Wonderfully composed activity though, cheers!

  96. Tony:

    I like the “1 one because it is the least odd” interpretation. But I’d like to speak up about the last one – I find it the most… _grating_. It really unbalances the image. Maybe if the order was different it wouldn’t bother me so much. But it does. So my natural inclination is to say that the last one is the most odd. It is, visually, to me, the most odd. Just a data point for those that think color or shape or border is the most obvious. Not to me.

  97. Odd one out | justpuzzles:

    […] the other was completely right. While surfing around this week I encountered another odd one out at Tanyas blog, see the illustration above. No solution given this time, and rightfully so. You are welcome to […]

  98. salahuddin:

    I would say the second one 🙂

  99. Colin:

    I really enjoyed this. Thank you.

  100. Найди лишнее | Блог Хеллера:

    […] В комментариях подсказывают, что у задачки есть автор. Более того, автор оказался очень интересным для меня […]

  101. Siddhartha:

    The fourth one. It has got two(Black & White) frames or three colors(Red, Black & White).

  102. chris:

    I dont think any is any odd one out. Thy’re all shapes. They’re all colored and they’re all unique. LOL..cute though!

  103. chris:

    I dont think that there is any odd one out. Thy’re all shapes. They’re all colored and they’re all unique. LOL..cute though!

  104. neXus:

    At first glance I thought that the first one was not odd. But after I noticed that every other shape was odd in some way, the first one suddenly became the most odd shape of all, just because of the fact that it was not. But because each shape (even the first) is odd because of one particular property, which I all consider to be equally relevant, none of them are.

    It reminds me of a dilemma about a man who committed a crime. He was put in a cell and told that he would be executed some time the next week. But the exact day of his execution would be a surprise to him. So he figured:
    It can’t be on friday, because if I wasn’t executed by thursday it would no longer be a surprise.
    It can’t be on thursday, because if I wasn’t executed by wednesday, and it won’t be on friday, it would no longer be a surprise.
    It can’t be on wednesday, because if I wasn’t executed by tuesday, and it won’t be on thursday or friday, it would no longer be a surprise.
    It can’t be on tuesday, because if I wasn’t executed on monday, and it won’t be on wednesday, thursday or friday, it would no longer be a surprise.
    It can’t be on monday, because it won’t happen later in the week, so that would no longer be a surprise either.
    So it can never be a surprise and thus I will not be executed..
    The executioners came on wednesday, it was a total surprise.

    None of the days can be a surprise, and therefor all of them are.
    All of the shapes are odd, and therefor none of them are.

  105. Paitence:

    They all are. The answer in that differences can be found in all of them. They are all odd in their own way.

  106. Paitence:

    Funny enough, to answer Arthurs question. In that they are all the odd one out makes it so none of them are the odd one out. It is kinda of a dual answer.

  107. Hay uno que sobra - Mis Adivinanzas:

    […] propuesto por Tanya Khovanova como mofa a las preguntas del tipo: “¿Cuál sobra? o ¿Cuál es diferente?” de los […]

  108. onecae:

    The test question should clarify that criteria for judgement is limited to shape, color, size and outline. If that’s the case:
    All have shape;
    all have color;
    all have size.
    All except one has an outline.

  109. IvanLur:

    Probably been answered before, but I suppose I would add certain “stat value” to it.

    They all are the odd one.
    – One non-outlined.
    – Different color.
    – Different shape.
    – Different size.

  110. I am correct:

    They are not all the odd one out, the red, large, square outlined shape is the only one that can not be described as the only one without one of the factors. The answer is the aforementioned red, large, outlined, square. It could be argued that this makes it the only one that follows all of the rules but that would be stupid because it is changing the criteria for the word unique. The idea is that this is the only one that is not unique, making it the only unique one.
    color (red, green)
    size (large, small)
    shape (square, circle)
    outline (yes no)
    red, large, square, outlined — unique
    red, large, square, not outlined — only non outlined
    red, large, circle, outlined — only circle
    green, large, square, outlined — only green
    red, small, square, outlined — only small

  111. Celeb:

    simple answer. it’s the one on the left. some people think they are smart by saying it’s clearly the green one or it’s clearly the circle, drawing asinine conclusions. anyway the one on the left is the only shape that has only one different property from the rest of the shapes while the other shapes have 2 unique differences fro the other shapes (excluding the one on the left) which makes it the ‘odd’ one out.

  112. daNo:

    I agree with Mary’s logic (Oct 2009) – it’s the one on the left.

  113. Johnny D:

    Ummm… Boundaries should not hinder my decision, nor should open ends, nor should corners, nor should color, nor should size but I also guess indecision is not an option? I have an issue before I choose, the issue is that the question does not include circumstance. Why should I choose any shape if I do not have a problem to solve? Simple choosing a shape at random doesn’t really make sense to me. :/

  114. Chris:

    It’s the one on the left . It’s the only one that is not an odd one out.

  115. wdp:

    Second one. ( even after reading all comments )
    3 things why it’s odd:
    1) has only one color
    2) Smaller than 3 others and bigger than 4th.
    3) consist out of only one figure – square.

  116. wdp:

    Second one. ( even after reading all comments )
    3 things why it’s odd:
    1) has only one color
    2) Smaller than 3 others and bigger than 5th.
    3) consist out of only one figure – square.

  117. rp987:

    The leftmost red suqare with a black border.

    each of the rest would be considered odd one out aside from this square.

    2nd – no border
    3rd – Round
    4th – Green
    5th – Small

    by definition – they’re all odd out aside from the first, making it the most odd among odds.

  118. vml:

    It’s the sixth one; it’s invisible

  119. matt:

    All but the second have black borders. So the second one is the odd one out!

  120. lancel adjani ou je veux aller un peu plus loin et l:

    […] nivSac Lancel. Au final, un patron sur deux ne connait pas le montant de sa facture. ???????: Tanya Khovanova’s Math Blog

  121. Jaijith Balagopal:

    Here is an engineers solution for this puzzle from India.
    It is about black and white outline
    Probably the second cube is extruded towards front as you view in the picture above,while other four are extruded or projected inwards,considering them as standard engineering drawing views

    Black outline truly indicates the shadow of the portion
    behind.White outline is extrusion of that shape towards front side.

    So odd one , which is red square without outline,is a 3d figure projected towards front,while all other black outlined geometric views are projected towards back

    So you see the back face in the case of one without black outline and front face for one with black outlines

    And probably that circle is a cone in 3d.My explanation is based on rules of Engineering drawing.

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