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This puzzle is said to be from a Russian test and has an obvious but not fully fitting answer:

enter image description here The task is to find correct picture to replace question mark.

The "obvious" pattern is

that a small "snake" or 2 triangles goes down from top to bottom, from left to right. Then the answer is A.

But of course in this case the 5th picture must still have a triangle in the middle. That is one reason to dislike this answer; another would be that it doesn't explain why only 2 triangles move and the 3rd stays still.

I can't solve it. Maybe you can?

P.S. Word-by-word translation of the Russian text from the picture:
Question
What from the following replaces question mark in the given sequence?

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  • $\begingroup$ Anyone can translate the Russian text? Perhaps there are hints in it. $\endgroup$ – leoll2 Apr 26 '15 at 15:16
  • $\begingroup$ Also, have you verified that the correct answer is A? $\endgroup$ – leoll2 Apr 26 '15 at 15:22
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    $\begingroup$ @leoll2, I don't think there are hints in words, this is not a riddle, but I added word-wise translation to the question. I can't verify which answer is correct, unfortunately. $\endgroup$ – klm123 Apr 26 '15 at 15:29
  • $\begingroup$ Do you mean that following the obvious pattern, the 5th picture should have a black triangle in the middle of the bottom row? $\endgroup$ – jarnbjo Apr 26 '15 at 19:19
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    $\begingroup$ To be honest, I don't see any "obvious" pattern here at all. $\endgroup$ – cfh Apr 27 '15 at 14:14
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There are 3 black triangles on a field with 9 cells. To move a black triangle to an adjacent cells takes one step.

  • From 1 to 2 takes at least one step
  • From 2 to 3 takes at least two steps
  • From 3 to A takes at least three steps
  • From A to 5 takes at least four steps (triangles overlap now).

So A is the answer.

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  • $\begingroup$ 2-3 is 1 step.. $\endgroup$ – ev3commander Jun 2 '16 at 0:54
  • $\begingroup$ @ev3commander no, you can only move to an adjacent field (a field next to the current field) $\endgroup$ – Albert Hendriks Jun 2 '16 at 5:15
  • $\begingroup$ This could be the case... I accept it at the moment, since there was no other answer in 1 year, which fit to all 5 pictures. But I don't like it, because it doesn't allow to predict the sequence, only to chose between given answers. Good job anyway. $\endgroup$ – klm123 Jun 2 '16 at 5:44
  • $\begingroup$ @klm123 I see what you mean, but imho a hard IQ question should have something random you should ignore, while still having a simple solution. $\endgroup$ – Albert Hendriks Jun 2 '16 at 5:54
  • $\begingroup$ @AlbertHendriks, yeah, I think this must be the intended solution. I just don't like it :D $\endgroup$ – klm123 Jun 2 '16 at 5:58
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How about this solution:

There's a white field with a black triangle at the bottom. And there is a three-piece snake, consisting of a white triangle followed by two black triangles walking down this field. snake

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  • $\begingroup$ I prefer solution "The snake has eaten 3rd triangle" ;) All those doesn't look better then any other rule, which can be seen in first 4 pictures and makes 3rd triangle disappear. But this is not good... $\endgroup$ – klm123 May 7 '15 at 13:27
  • $\begingroup$ I was about to give the same solution. Then I saw yours. So I added my picture here. $\endgroup$ – Florian F Apr 23 '17 at 17:21
  • $\begingroup$ How do the second left step change to the third left step? $\endgroup$ – Hans Jul 12 '18 at 3:47
  • $\begingroup$ @Hans, 1, 2 and 3 all move one cell forward, with 1 wrapping around. $\endgroup$ – Ishamael Jul 13 '18 at 2:43
  • $\begingroup$ I am sorry, it was exactly the 1 I had problem with. Could you please describe precisely what you mean by "wrapping around"? $\endgroup$ – Hans Jul 15 '18 at 4:55
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Not (yet) a solution, but I made some colorings which might help with finding a pattern and numbers to help explain the pattern to others:

(colored triangles)

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I believe this is the correct answer.

What I notice here is

One white triangle is moved each turn AND one is added, either in the 4th or 5th step.

If the rules of play are:

1.You can move one white triangle per turn.

and

2. you can (optionally) add one white triangle per turn.

Then A is the only possible answer that can lead to diagram 5 following the observed "rules".

The problem with B is that you inferred that they move to neighbors. The 5th spot and available answers suggest you need to re-evaluate your assumptions. Given the available information, A is the best available answer because there isn't a logical progression from B to diagram 5.

Insinuating a pattern, where one does not exist is classic. Was it a functional IQ test? Military?

ps. if you insist on the snake interpretation, maybe the mouse had no reason to move until the snake arrived, catching it in the next move. I like my answer better :)

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My Answer

It is A in my opinion (I'm gonna sound crazy)

Given this patter of numbers:

enter image description here

Given an increment in the current mini-triangle with every big triangle then I an proposing that the previous triangle must be able to cover the current mini-triangle (which is white) in a black mini-triangle. Therefore A is perfect as it for fills both of my rules. The first triangle already has a black triangle on the first mini-triangle.

enter image descriptionhere

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  • $\begingroup$ Its like the game where you must guess the "number" that a configuration of objects represents and it almost never makes sense as the answer is actually not what you would expect (its the amount of fingers present on the table of the magician). So all the other squares it simple to hide the pattern, and the reason it doesn't have a clear pattern is because it is being concealed. $\endgroup$ – Daedric Apr 30 '15 at 21:27
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Considering the sequence and the possible answers it seems clear that there are three black triangles, two of which are overlapping in the last situation. From the first to the last situation is four steps. None of the rules of movement that I could come up with would explain the intermediate and final situation if applied four times.

So maybe it is not movement but change. I got pretty excited about this rule: "change the first (left to right, top to bottom) black triangle to white, the next first white triangle to black" (giving answer A), but it cannot explain overlapping triangles, and thus cannot explain the final situation.

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I've spent a lot of time on this, I still do not have a full answer but do see a pattern that fits the so far preferred answer - A. I haven't been able to detect a pattern with the other answers.

Possible pattern]1

Because there are an odd number of triangles there must be something different about the rule for at least one triangle. I can provide a speculative explanation with my cyan dot but am not entirely happy with it.

Maybe someone can build on this to provide the final logic?

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  • $\begingroup$ Arrrgh!!! This is sending me crazy. I realise the red dot is incorrect, I'll have another crack when I have time. $\endgroup$ – jphor Jun 2 '16 at 9:34

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