This question already has an answer here:

Note: This puzzle cannot be solved on the computer. Draw it out on paper and then solve...

|               |              |
X               X              X
|               |              |
|        |             |       |
X        X             X       X
|        |             |       |

Rules: With a single "line" starting anywhere, pass through each X only once.

Answers can be described (as there is more than one way to do it) or scanned and posted.


marked as duplicate by Sconibulus, greenturtle3141, Beastly Gerbil, Deusovi May 11 '17 at 20:01

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • $\begingroup$ Agreed - this is a duplicate of that question. $\endgroup$ – Jeff Zeitlin May 11 '17 at 19:58
  • $\begingroup$ Yes, I guess it is. Sorry about that. I thought I had looked, but not hard enough. Although, I will have to add my own answer to the other question. $\endgroup$ – ben-Nabiy Derush May 11 '17 at 20:11
  • $\begingroup$ Have you tried folding the paper in half to continue your line after a portal jump? $\endgroup$ – Ian MacDonald May 11 '17 at 20:11
  • $\begingroup$ I added the answers I remembered to the original post (as mine truly is a duplicate, although slightly different in wording) $\endgroup$ – ben-Nabiy Derush May 11 '17 at 20:19

This puzzle cannot be solved. Since you can only pass through an X once, one end of the path must be in each of the three large rectangles, and one end must be outside the overall diagram. Since that's four ends, and a line has only two ends, the puzzle cannot be solved as presented. The referenced duplicate question has as one of its answers a detailed explanation of why it's impossible; a simplified explanation (and the one that I immediately thought of) was included, without diagram, in the story "The Sixteen Keys" in Lord Darcy, a collection of Randall Garret's stories about the eponymous detective.

  • $\begingroup$ Actually it can be solved, but it takes thinking outside the box. I missed that someone else posted the question, but it is doable. $\endgroup$ – ben-Nabiy Derush May 11 '17 at 20:10
  • $\begingroup$ @ben-NabiyDerush If you have a solution that hasn't already been posted on the linked duplicate question, feel free to post another solution there. $\endgroup$ – GentlePurpleRain May 11 '17 at 20:28
  • $\begingroup$ @GentlePurpleRain - Done. $\endgroup$ – ben-Nabiy Derush May 11 '17 at 20:36

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