Difficult puzzles, brain teasers and conundrums

Puzzles, riddles, brain teasers, conundrums, logic questions in pictures. All the logic questions here are more difficult than the average in other sections of the site. You will most likely need more time to complete them than usual. But you can look at the answers and explanations for all these logic riddles, brain teasers and conundrums. To check your answer, click on the «Answer» button located below the task. After this, the correct answer and explanations will appear. Below you can select other questions on this topic. Typically each topic has 20 questions or more. At the same time, the complexity of logical problems gradually increases. First there will be easy questions, then medium, then difficult. Try to complete tasks as quickly as possible.
Question - 12
In this brain teaser you need to choose the correct version of the square with lines inside. You need to understand the rule by which the lines inside all the squares are built. You may need to think outside the box.
Correct answer = 6.
Here each square intersects two lines. Moreover, each such line intersects two squares. Along these lines a trace is formed inside the squares. Based on the direction of the lines in adjacent squares, further propagation of the lines can be assumed. As a result, you can determine the correct version of the square to place instead of the question mark.
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