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-   -   Today's Challenge - Find the fault in the ladder (http://www.logic-puzzles.org/forum/showthread.php?t=288)

 BillsBayou 06-04-2013 06:37 PM

Today's Challenge - Find the fault in the ladder

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I was going to post this one with a plea for help, then I figured out the approach while I was typing the title. I stared at this one for half an hour and found nothing, but the light goes off when I come here. Gee but this forum is so helpful. I got the answer before I posted! You guys are awesome.

Ok, so here's the puzzle in it's blank state:

Attachment 63

I'll post the puzzle at the bottleneck in the first reply to this post.

 BillsBayou 06-04-2013 06:40 PM

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Here's the puzzle at the bottleneck. Don't look unless you've really worked it over. There are some complementary exclusion sets and 2x2 sets in there that took me a few iterations to develop. I don't want to spoil your fun.

Attachment 65

At this point only clues 7 and 8 are left.

Can you figure it out from here? I'll post the key to solving this in a later reply if anyone asks; but not until asked. ;)

 shriekingviolet 06-04-2013 08:50 PM

Oh my gosh, that one was hard! It took me forever to get my filled-in grid to match yours, and then another eternity before that last epiphany hit. I am having a pretty bad brain fog day today though. But I got it eventually.

 zenobia43 06-04-2013 08:53 PM

I hope this isn't spoiling anything, but the key to this solution, starting from the "stuck" screen shot, is found in a very recent post on this subject.

The symmetry of the open spaces in this puzzle is scary. This is what it looks like if an X was misplaced or a clue was misinterpreted. All those open rectangles beg you to hit the reset button or start trying some of the limited choices that remain to see if you can find a conflict quickly.

The two remaining clues and other available information are all that is needed to solve this with pure logic.

 BillsBayou 06-04-2013 09:09 PM

Quote:
 Originally Posted by zenobia43 (Post 1167) I hope this isn't spoiling anything, but the key to this solution, starting from the "stuck" screen shot, is found in a very recent post on this subject.
Yes. Those who fail to learn from history are doomed to repeat it. Pretty much sums up me. Ask my wife for more examples. :rolleyes:

Quote:
 Originally Posted by zenobia43 (Post 1167) The symmetry of the open spaces in this puzzle is scary. This is what it looks like if an X was misplaced or a clue was misinterpreted. All those open rectangles beg you to hit the reset button or start trying some of the limited choices that remain to see if you can find a conflict quickly.
Yeah. Scared me too. I saved a screen shot then hit reset. Then I built the same exact puzzle again.

Quote:
 Originally Posted by zenobia43 (Post 1167) The two remaining clues and other available information are all that is needed to solve this with pure logic.
That's what they tell us. So far, it appears to be true.

 BillsBayou 06-04-2013 09:11 PM

Quote:
 Originally Posted by shriekingviolet (Post 1166) Oh my gosh, that one was hard! It took me forever to get my filled-in grid to match yours, and then another eternity before that last epiphany hit. I am having a pretty bad brain fog day today though. But I got it eventually. I have really enjoyed reading through your threads on the hard puzzles/advanced logic. I've learned a lot. :)
Glad you enjoyed this one. Happy to hear you could get as far as I did. This one does require a good long massage before giving up its secrets.

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