# It’s the Friday Puzzle!

92

Please do NOT post your answer, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.

Can you place six X’s on this noughts and crosses board without making three-in-a-row in any direction?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

## 92 comments on “It’s the Friday Puzzle!”

1. 10 seconds. Hope I’m not doing it wrong

2. Chris says:

Easy unless I’m missing something ? 10 secs

3. Anonymous says:

15 secs

4. Garry says:

Solved, <5 minutes.

5. Chris says:

Slightly more interestingly, prove there are only two solutions.

6. Kristian says:

A minute, because I had to open paint. I don’t think my solution is the desired one though.

• Eddie says:

If it’s right, why wouldn’t it be?

7. Yup, got it. Approx. 30 seconds.

8. Geodetective says:

15 seconds or so.

9. Baker's Dozen says:

Yes. What’s the puzzle? And what’s a naught?

• A “naught” is “nothing”, or the number zero: 0.

• One Eyed Jack says:

Tac-Tac-Toe for those of us on the other side of the pond.

• Norman Smith says:

A “naught” is the elementary particle of naughtiness. Sometimes written as “naughton”, pronounced, “Not on!”

10. sushey says:

Five minutes to clean the whiteboard, five minutes trying, 10 seconds after finding a different approach.
Nice one, I really like this puzzle!

11. Anne Elk says:

12. Anonymous says:

yes …. sssssss

13. Eddie says:

Got it on second attempt. Great puzzle.

14. Anonymous says:

too easy

One second
As many different solutions as you like.
Suspect my answer may not be the one Richard gives however.

30 seconds to get what I believe will be the official answer

• Lazy T says:

I bet you put all siXs in the middle square, eh?

Something like that Lazy T.
I don’t want to be too specific, in case my first answer is the official one.

• ChrisR says:

so, you’re playing 3D noughts and crosses – and have got a vertical column!

Maybe, but I also have a infinite number of 2D solutions.

16. Chris says:

Done

17. ivan says:

I would be interested to Chris’s proof of two solutions, because I have a proof that there is only one solution (treating rotations and reflections as equivalent).

• sirkitkat says:

Shift your solution 1 square in any direction and you’ll find an other one ðŸ˜‰
(if some of the x fall off the board, add them on the other side)

• ChrisR says:

Not convinced about that shifting – I end up with a three in a row

• Ken Haley says:

Right, but if you DO count rotations and reflections, there are only two solutions.

• sirkitkat’s idea of shifting everything one space sideways doesn’t work, because it creates a row of three where one did not exist before.

• sirkitkat says:

Right, overlooked something there ðŸ™‚

18. Pitmonster says:

Got in less than 30 seconds.

First one I’ve got in a while though

• Chris says:

Well, if you’re going to treat rotations and reflections as equivalent…

19. Doraemon says:

Solved less than 15min ðŸ˜€

20. pen and paper 10 seconds

21. ChrisR says:

Yes, < 10 seconds

22. 2 unique solutions, taking account of rotations etc.

23. Ratt Mutter says:

Pen and paper… under 10 seconds!

24. mgm75 says:

Figuring it out in about ten seconds.

25. mittfh says:

About half a minute or so, brainpower only (imagining the positions rather than drawing them). I wonder how solutions there’d be for twelve Xs on a 4×4 grid / twenty Xs on a 5×5 grid?

26. Stevie says:

Maybe twenty seconds. It’s interesting that nobody’s chuntered about Dave’s spoiler. I guess readers have realised how easy it is to try solve the puzzle before looking at comments.

27. Anonymous says:

Doesn’t say anything about them having to go in the boxes…

• Anonymous says:

15 seconds or so. It’s even easier if you flip it to say “Can you play three O’s in a way which stops X making a winning line? OR I’ve got it horribly wrong and embarrassed myself on the Internet. And not for the first time…

• Hugh Janus says:

I’ve seen the photos

• Slange Navarr says:

Brilliant, Janus. Thank you, as ever, for your laser-sharp one-liners. It would be a dark world without your wit.

• ChrisR says:

re first couple of comments – – it’s a noughts and crosses board – there are certain areas which are out of bounds ðŸ™‚
and i do like the idea of the complementary problem with the 3 ‘O’s – that’s like playing the game and stopping your opponent from winning

28. Miss Chili says:

5 seconds, else I’m wrong as rain!

29. Anonymous says:

By far the easiest Friday puzzle I’ve seen in a while! It took longer to find a pen and paper than to do it!

30. sowmya says:

10 seconds max

31. Skatz says:

10 seconds, easy one this week

32. Anonymous says:

solved..in 21 seconds

33. Brock says:

Yup got it in one second.

34. james says:

5 seconds…

35. james says:

• I Luv Non-Sequiturs says:

Keep em coming James dude

36. ross says:

yes

37. It took me 3 tries and about 15 seconds. I started intuitively, and when that failed the 2nd time, I went about it algorithmically, which worked right away. It’s a nice, easy puzzle which activates our puzzler just enough to feel accomplished, which brings down our guard for upcoming, more devious games.

38. Bert says:

I love how every Friday there is a new puzzle posted and in the direction it says “Do not post the answer” but consistently, some twit within the first 0-20 comments has posted the solution. Takes all the fun out of it. Thanks Dave.

• Mr Self Righteous Twat says:

I agree Bert.
You are so right.
We could practically be related.
Do you have the same surname as me?

• Mr Moderator says:

Now Now Children….

• Mr Self Rightous Twat says:

It’s not fair!
Bert started it!
Besides, the Self Righteous Twats have a noble lineage and are one of the oldest families in the country.

39. rmb says:

A minute

40. Skip says:

41. Anonymous says:

10 seconds. Then 5 more seconds with a mirror. XD

42. Suzuki says:

8-10 secs

43. Jeff Scanlan says:

44. Peter says:

Third attempt..

45. Joshua Prettyman says:

46. VicinCA says:

< 30 s with paper and pencil

47. I think there is only one solution. But if you rotate the grid through 90 degrees, you get what looks like a second solution. I count the two as just one solution. Has anyone got a solution that is not “the same” in this sense?

48. About 20 seconds. I found it easier to do the negative of the puzzle, i.e. placing three crosses in places where they would block all possible rows of three for the other six places.

49. Paul Durrant says:

• Anonymous says:

Obviously it would have been more impressive if you had got the answer without reading the question.

50. Fotoflex says:

Got it. Third attempt.

51. Isn’t this just completely trivial and obvious? Took about 3 seconds to draw.

52. Hal Harris says:

Very easy one.

53. Yordoc says:

about 3 secs … too easy

54. Calgacus says:

Infinite number of solutions possible, but got one that Richard might agree with.

55. Cymon says:

Took me an embarrassingly long 30 seconds to figure that out.

56. Teun Spaans says:

nice one, but easy

57. Phil H says:

I also managed to put six noughts on the board at not get three in a row

58. Tom says:

Yes. Yes I can.

59. Caoimhe says:

Just got it in 30 seconds.

60. Hazel says:

About a minute, altogether. Tried 2 different ideas, only one worked!

61. Anders says:

not too difficult. but as usual the wording allows a trivial non-solution solution. three xes slightly off center in each box makes them not align in a row. but even without such nonsense about 30 seconds

• ChrisR says:

you’d be a gas playing noughts and crosses with

62. Diane says:

About 10 seconds once I finally got frustrated and picked up a pencil.

63. Anonymous says: