Puzzle Description:

of Apple

#1: Adam Nielson (monkeyboy) on May 13, 2009 [HINT] [SPOILER]

If you turn the image on it's side, it looks like a slice of apple PIE, not just an apple. Using edge logic was the only way to solve it.

Found to be logically solvable by jan.

I really liked this....but ONLY because it was chewable...any larger and the constant trial and error (what everyone seems to call edge logic) would have driven me nuts.

ANY solvable puzzle is "logically solvable" if one uses "edge logic" so I'm confused by the determination "logically solvable".

I still liked this puzzle because it was small enough not to take an age and a half to solve by trial and error.

Well, some people use the word "edge logic" quite liberally, and some of the puzzles they claim are solvable by "edge logic" don't appear to be so to me.

There is an explanation of edge logic on the "Advanced Puzzle Solving" page, but I probably have to revisit it, because a lot of people don't get it.

Suppose the first column of the puzzle has just one clue: "3".

Suppose the second column of the puzzle has the clue "1 1".

Big number along the edge, and smaller numbers further in, that's a sign that edge logic might work. To make it work, we look at the first numbers of all the row clues. Suppose all of them were 2 or larger.

Then we'd know the puzzle was erroneous and impossible to solve, because anyplace you placed the "3" in column one, the row clues would all fill in at least one cell in column two, and you'd have a three in column two, which can't be there. There can only be ones.

But suppose we look closer and fine one row clue that starts with a "1". Aha! We're saved. The three in column one can be placed straddling this "1" row, so in column 2 there'd be two blacks separated by a dot.

That's the pattern. You look at the placement of a block along (or near) the edge, in this case the 3 in column 1, and look for positions that are compatible with clues in some line a bit further inward (in this case column two). I find this very easy to do without needed to mark and undo. It takes a little counting and cross-checking, but so does regular line solving.

Looks more like a steaming slice of pizza to me. This one was a bugger. My eyes are nearly watering from staring at the screen trying to find what I was missing. A couple of attempts and suddenly things started to pop into place.

Wow, that was hard. I used edge logic, but I also had to use trial and error because I couldn't think far enough ahead in my head. I couldn't tell what it was until I read the description. But, I still enjoyed solving this, since is wasn't too big.

Ditto Teresa!

it also could be a butterfly with it's wings back.
tough but fun to solve...because it was small as JoDeen said.

I totally see the butterfly, too!

Nice puzzle

I used some edge logic but still got stuck for a bit before I jumped to some look-ahead. No guessing, but I did have to look ahead. It went like this:

If the 2 in R5 starts in C4, then the 6 in R5 forces dot in C4R6, putting a black in R3. At the same time, The dot at the end of that first 2 and the black would happen above it from the 4 in R4 puts another black dot in R3, violating the row. Therefore, C4R5 has to be a dot. Then it solved with simple line logic.

Good puzzle. Small, challenging.

Thanks.

I tackled this one slightly different but in the same area. Perhaps just a different way to think about it.

Looking at the 3 clue in column 4, imagine it being in R3C4-R5C4. Now focus on how this will affect column 6. R3C6 and R5C6 would be dots and R4C5 would be black. This contradicts column 6, so R3C4 is a dot.

Again looking at the 3 clue in column 4, imagine it being in R4C4-R6C4. This time look how it affects column 5. R4C5 and R5C5 would be blacks and R6C5 would be a dot. This makes column 5 invalid, so R4C4 is a dot. Moving down one more in column 4, we can see that R5C4 is also a dot with the same logic.

I then used simple edge logic in row 1 to see that R1C6 was a dot. The rest solves with line logic.

great solve

Lol...what a difference 5 years makes! Now, edge logic is challenging and fun to me,, even on larger puzzles. I think this image is amazing because it truly looks like several different images...slice of apple, butterfly...satyr's head...goat...

Tough to see.

This is the hardest little puzzle I've ever seen. I enjoyed it because I grew from it. I love advancing in logic. Although I didn't figure it out myself, Gator's explanation in his hint taught me something. I look forward to getting better at edge logic.

Aurelian - if that thought that little puzzle was hard, you should try #6302. http://webpbn.com/6302 :)

It's not a slice of apple, or apple pie, or a butterfly -

It's Van Gogh's ear, after he SLICED it off ...

Re: the "Edge Logic" discussion, I rather enjoy when my line-logic-only pbn strategy turns into a little mini-game of Battleship before I can resume line-logic'ing my way to the solution.

D4? [check] MISS! :(
E5? [check] HIT! :D

so you enjoy that more than trying other forms of logic?

It boils down to a matter of knowledge; I enjoy WPBN-battleship more than I would seeking the knowledge of other forms of logic to apply, though I know they exist. :)

gotcha, i was just genuinely curious :) sounds a bit like when we'd get stuck in Minesweeper and there was no more logic, but a shot in the dark fingers crossed :)

One of the ways that PBN puzzles are better than Minesweeper. :)

Yaaaaas! A wrong click doesn't end the game!

One of my kids found an online multiplayer Minesweeper game that was really intriguing to play -- an interesting mix of cooperativeness and competitiveness, playing against a small handful of people from all over the world. But I don't think it's around anymore -- the URL where it used to be now brings up something else instead.

Goto next topic

You must register and log in to be able to participate in this discussion.