There are 10 squares in the figure. Move 3 matchsticks to create 17 squares. Squares don't have to be equal in size?

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  • $\begingroup$ $Move$ 3 matchsticks or $Remove$? $\endgroup$ – Seyed Dec 28 '17 at 17:06
  • $\begingroup$ Mostly likely move... Remove would be impossible? @Seyed $\endgroup$ – Quintec Dec 28 '17 at 17:07
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    $\begingroup$ The obvious solution has 17 squares and one extra match sticking out like a sore.. stick. This is, in general, an uncool thing: all the matches should be meaningful parts of the solution. I hope there is a less obvious solution that makes use of all the matches. $\endgroup$ – Bass Dec 28 '17 at 17:12
  • $\begingroup$ It also means there is no unique solution. The sore-stick solution can be formed in 16 different ways. $\endgroup$ – ekhumoro Dec 28 '17 at 22:02
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    $\begingroup$ Assuming there really is no clever "other solution", I'd like to suggest a slight modification: remove the middle stick in the vertical line of 5 sticks, and transform the problem into this famous one. Notice the lack of sore sticks, how the starting position is 4-way symmetric and the answer is not, and how all the squares in the starting position are non-adjacent, and the answer has squares crammed in as tight as possible. $\endgroup$ – Bass Dec 28 '17 at 23:44

The answer is:

enter image description here


Let's name the sticks.

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Here 17 squares are- (1) ABCD, (2) GHIJ, (3) STUR, (4) CELM, (5) EFKL, (6) FKZJ, (7) KZWX, (8) LKXY, (9) MNYL, (10) NOPY, (11) PQXY, (12) QRWX, (13) CNXF, (14) MOQK, (15) EYWJ, (16) LPRZ, (17) CORJ

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    $\begingroup$ And it even has the antenna at O, with which it can communicate to the alternate universe where it’s ok for a matches puzzle to have matches left over after completing the objective. Not the answerer’s fault, of course, so here’s my upvote. $\endgroup$ – Bass Dec 28 '17 at 19:13
  • $\begingroup$ @Bass I don’t know... maybe you’re from an alternate universe where all puzzles have to be perfect? (Not trying to be an ass... but you seem to be hating a lot over a small thing.) $\endgroup$ – Quintec Dec 28 '17 at 21:49
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    $\begingroup$ @thecoder16, A good puzzle is always explicit about the desired objectives and the allowed means. Therefore, it’s very important to follow the generally accepted conventions, or at least add a note when deviating. In matchstick rearranging, some of the conventions are - no stacking - no breaking the matches - no overlapping - and, very importantly: no surplus. Otherwise the solution to this puzzle could be ”well, it clearly has two squares already. Just ignore the other squares.” $\endgroup$ – Bass Dec 28 '17 at 22:52
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    $\begingroup$ @thecoder16 Also, please accept my apologies for using such unprofessional language in my criticism. I was a bit riled up since this wasn’t the first matches problem with the exact same issue on PSE today. I got a bit carried away. Sorry. $\endgroup$ – Bass Dec 28 '17 at 22:59

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