peek at solution solve puzzle
quality: difficulty:
solvability: deep lookahead
Puzzle Description:
I don't know who she looks like!
#1: Josh Greifer (joshgreifer) on Mar 19, 2010 [HINT]
The puzzle *can* be solved without guesswork:#2: Tom O'Connell (sensei69) on Mar 19, 2010
The top left horizontal 4 can only go in one place.
After you've put that in, the "3" in the 2 3 2 row is constrained.
I solved this puzzle w/o guess work!#3: Gator (Gator) on Mar 19, 2010 [HINT]
I'm not seeing how the top left 4 can only go in one place. Could you describe how you determine that? Thanks!#4: Josh Greifer (joshgreifer) on Mar 19, 2010 [HINT]
Hi Gator, there are five places the first 4 or the 4-4 can go, but all except placing it at the top left, lead to a "red dot" on row 2, or on another row.#5: Gator (Gator) on Mar 19, 2010 [HINT]
If you lay it along columns 2,3,4,5, for example, it leads to this:
12345
1 XXXX
2.X.X. <-- row two (1,2,1,2) is illegal
3 . X
4 .
Similarly with the other positions -- all lead to an inconsistency.
Placing it on columns 5,6,7,8 seems okay at first, but eventually leads to an inconsistency with (if I remember correctly) the fourth row with a singe 2.
Josh
We do classify this type of reasoning as guessing. If you have to look more than 1 move ahead (rarely 2 if it is easy to see), these are not considered logically solvable without guessing.#6: Josh Greifer (joshgreifer) on Mar 19, 2010 [HINT]
Okay, I began to suspect that's what it means -- I'm new in these parts. This puzzle is definitely not soluble without thinking through more than one move ahead. Seems a little harsh to give a puzzle a question mark when you need to do that kind of analysis, though. I think an exclamation point would be better :)#7: Adam Nielson (monkeyboy) on Mar 19, 2010 [HINT] [SPOILER]
It kept looking like a pig.#8: Web Paint-By-Number Robot (webpbn) on Mar 21, 2010
I used symmetry to get the bottom half, and then it solved from there.
Found to require some guessing by jan.#9: Jane Doe (telly) on Apr 4, 2010 [SPOILER]
she's kinda scary looking.#10: David Bouldin (dbouldin) on Oct 3, 2011 [HINT]
i would contend that i just solved it using logic alone without looking ahead to trigger the "requires some guessing". complicated edge logic? yes. guessing? no.#11: Kristen Vognild (Kristen) on Aug 26, 2012
here are the main two spots that broke me away from stuck points:
- no matter where the first 4 in R1 goes, C4R2 will always be red (and must be part of the 2 in R2...that helps later)
- after you have three of the 4 in C13 and the 3 in C 12, look at how the 2 in C12 is going to come in...in R1-7 only one row (R5) ends in a 1, but there are two 1's in C13. this means that one of the ones will trigger the 2, one has to "hide" (meaning not trigger anything) on C13R5 AND the 4 can't trigger the 2 by extending into R7.
I don't know what that logic is called. but it is a form of edge logic. what do you think?
I would venture to change it to "solvable with deep lookahead"#12: Web Paint-By-Number Robot (webpbn) on Aug 27, 2012
Found to be solvable with deep lookahead by jan.#13: David Bouldin (dbouldin) on Aug 27, 2012
seems fair#14: Joe (infrapinklizzard) on Feb 5, 2018 [HINT]
David has some good points.
Here's my solve:
Line Logic gets symmetrical splashes on the bottom corners.
The two 1s in c13 cannot both extend into c12 without a conflict so one must be crossed by a 1. The only place that happens is in r5, so c13r5 must be red.
ll
Then two bits of deep lookahead:
the remaining 1 in c13 can go in three positions:
> r3 > it will start a zig-zag-- going down runs into an error in c11; going up also runs into an error in c11 -- so r3 is bad and must be white.
> r2 > it will start a zig-zag -- going down runs into an error in c11; going up also runs into an error in c11 -- so r2 is bad and must be white.
LL
Edge Logic 3 r9 = c4 w
LL
another deep-lookahead:
no matter where the 4 in r1 goes, r2c4 will be red.
LL to finish.
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