All entries for March 2011

March 25, 2011

Friday Puzzles #97

So something very curious happened this week. This puzzle appeared on

My unquestionably loyal readers will doubtlessly recall this puzzle as featuring on this very blog back in July 2010:

You don’t need to know what a dihedral group is to recognise that these puzzles are relates by a reflection in the bottom-left/top-right diagonal. I don’t want to go into this too much on the blog – I have initiated a discussion here – but suffice to say I think this is a rather eye-opening coincidence (rather than malicious plagiarism) based on the fact that actually Masyu with twisted symmetry are very highly constrained, and the creative puzzle author might put down the initial diagonal pattern and then finish off the puzzle in exactly the same way as I did.

Anyway, I’m still a little unsure as to what to make of it all, so please feel free to leave a comment either here or in the forum thread.

And so to business. This week’s puzzle is inevitably a Masyu with twisted symmetry. The solve is nothing special, but I hope you’ll agree the design is at least a little striking. Enjoy!

#123 Masyu – rated easy

All puzzles © Tom Collyer 2009-11

March 18, 2011

Friday Puzzles #96

This week’s puzzle will be slightly delayed due to a slight hitch in the uploading process…more soon…


So back down to earth this week. I didn’t have access to my laptop earlier, but thankfully I was able to quickly cook up an inkscape template and save it directly to the right directory. Marvellous. Anyway, this puzzle isn’t so hard I don’t think, but you’ll want to watch your step. Did I already do a “4” themed Heyawake? If so never mind. Enjoy!

#122 Heyawake – rated medium

All puzzles © Tom Collyer 2009-11

March 11, 2011

Friday Puzzles #95

#121 Masyu – rated hard

All puzzles © Tom Collyer 2009-11

P.S. you lose if you use uniqueness strategies. That is all.

March 04, 2011

Friday Puzzles #94

Don’t Masyu look so much better with a nice bit of symmetry!? This week’s puzzle would probably count as a medium if it were 10×10 rather than 18×10 – but perhaps that’s only because I don’t believe you can have a hard 10×10 Masyu. I’d say it’s definitely hard by standards. Included in this puzzle is a twist on an old chestnut, which nevertheless I haven’t seen before. Maybe I’ll send it to 11 some other time. Still, I reckon this puzzle isn’t so bad either. Enjoy!

#120 Masyu – rated hard

All puzzles © Tom Collyer 2009-11


Welcome to the blog of current UKPA sudoku champion, two-time Times national sudoku champion and general logic puzzle fan Tom Collyer.

Home of the original Friday Puzzles, each Friday I publish a 100% original and handmade logic puzzle, inspired by the world-famous Nikoli company.

How to play:
AkariFillominoHashiHeyawakeHitoriKakuroLITSMasyuNumberlinkNurikabeRipple EffectShikakuSlitherlinkSudokuSuraromuYajilin.


March 2011

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Latest comments

  • I like the appearance of the solution. :P Nice one. by Prasanna Seshadri on this entry
  • I think I've seen something vaguely similar in some of Palmer's puzzles as well. To be honest I've a… by on this entry
  • That's two puzzles in a row where I find something I had used before. I know, not plagiarism; just g… by Bram on this entry
  • Kota, that's not really true. I had made my puzzle before going to the WPC already. Also I don't hav… by Bram on this entry
  • About 20 minutes, after restarting from a mistaken conclusion. by Bryce Herdt on this entry

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