Puzzle Description:

Two knives crossing. Created by my 8 year old son, Teddy.

#1: Beth (Shasta) on Mar 10, 2008

Very nice Teddy! Are they cooking knives or fighting knives?

tell your son great job

I don't think this is logically solvable. I couldn't even get a start on it.

Can you post a hint or two?

I agree Jan. Impossible. Nowhere to start at all.

by guessing I got it. good for your 8-year-old.

i just started in the corner and guessed but it looks great when finished.
by the way, i don't usually even try ones that require guessing. no idea why i tackled this one.

Focus on the bottom row. Notice how all of the column clues start with black at the bottom. So the 3 clues on the bottom must be under the 1 green clues in row 15 (same thing on the sides and top). Given this, start to try to place the 3 clues, and you will find they will not go very many places. When you look at the possibilities and use some edge logic, you will find R16C5 and R16C11 have to be blank.

That is the only start I can find. I "know" based on the fact that the puzzle is "mostly symmetric" that columns 6 through 10 on row 16 will not be filled in, but that is not good enough to be considered a logically way forward.

After gator's comments, I went back and solved this. As usual, he was dead on. In fact, in row 15, there are only 5 places where the 2 single greens can be placed (C 2, 7,8,9, and 14). Knowing this means that AT LEAST one of the greens must be placed toward the edge (either C2 or C14). The other may be placed in the center portion, (C7,8 or 9) or over toward the other edge.

Assuming you place the first green in C2, the only place the 2nd green could go out of the center 3 squares is in C 9 (C7 is too close, and C8 violates R 13 and 14) and yet with a few more pixels placed, this also violates C7, thus forcing the second green 1 to be placed in C14.

Assuming you start with the green in C14, placing the other green 1 in C9 is too close, C8 violates R 13 and 14, and C7 would violate C3 after a few more pixels placed.

Thus, both the greens in R15 have to be in C2 and C14.

Similar logic can be applied to the top.

Yep, edge and diagonal logic to solve this one, so it can be modified to Moderate Lookahead.

Nobody has yet succeeded in explaining "diagonal logic" to me in a way that convinces me that it is actually "logic".

In this case, you can use edge logic on the black in the bottom corners.

Goto next topic

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