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Number: Puzzle #6506
Genre: Skyscrapers
Author: jama
Appeared at: October 24, 2020

Nice one. I found this to be tricky for a 2* but never needed to resort to trial and error. Each clue is well placed, nothing extra, just have to find the thread to pull to place the next number in the solving path. The reasoning isn't always that straightforward, which made this fun to solve.
Number: Puzzle #6246
Genre: Star Battle
Author: anurag.sahay
Appeared at: March 14, 2020

Nice little tribute!
Number: Puzzle #6157
Genre: Tapa
Author: anurag.sahay
Appeared at: July 14, 2019

Nice one! Took a little to figure out how to get started, but then it solved really nicely.
Why not just submit this in the studio in the Master Mind genre? Even if you allow duplication and the digit 0, this has a unique solution, so the normal rules of Master Mind on this site work for this puzzle.
Could it have to do with puzzles that you've solved that have since been pulled? And/or puzzles that are in your sandbox?
Yes, exactly! If you think of the shelves, ceiling(s) and floor(s) as nodes in a graph, the chains as down arrows, and the posts as up arrows, then the collection of all of them must form a directed acyclic multigraph, in which each shelf is pointed to by exactly two edges (either from two different nodes, or the same node twice). OK, maybe that's not the most intuitive way to think about it, but it's exactly as you said: treat it like a graph and ensure there are no loops.
I think the problem is that you are treating the 2-long chain piece on the left as going "through" the small shelf in the middle-left. But the chains don't go "through" shelves. You have to treat the top chain piece as connecting the middle shelf to the stable shelf above it, and then the bottom chain piece is connecting the longer shelf at the bottom to the small middle shelf, NOT the top shelf. The problem is, in this situation, neither the small middle shelf nor the longer bottom shelf is stable, as they rely on each other.

In your 3rd image, you can clearly see that all the shelves are stable, including the longer one in the bottom row. But when you add that extra shelf in the middle-left in the 4th image, you are splitting the chain of length 2 into two smaller chains each of length 1, and you have to treat those chains independently. This creates the situation in which two shelves not known to be stable rely on each other, which violates the rule that each shelf must connect only to the floor, ceiling, or other stable shelves.

Given that the puzzle solution is a static snapshot of the final shelf arrangement, I'm not sure how the placement order can reasonably be taken into account.

Ironically, this is what led to your confusion here, as you assumed the bottom long shelf was placed before the small middle one. In fact, placement order does not matter, and you should be able to prove, with only the final solution, that each shelf is stable independently, connecting either to only the floor and/or ceiling, or to other shelves you have proved are stable. Hope this helps!
Really nice puzzle. Great use of negative space. I do think this is more difficult than most 2-star puzzles, but no trial and error is needed. I found the solution path to this one elegant without being obvious at first glance.

boing: I've sent you a PM about the solution path.
Yeah, this puzzle took me way longer than it should have. Spent a while trying to figure out which unnumbered gate should be gate #19, until I realized there were only 18 gates...
Number: Puzzle #5367
Genre: Yajilin
Author: rob
Appeared at: August 1, 2016

Nice design!
Number: Puzzle #5341
Genre: Slalom
Author: BenMiff
Appeared at: July 12, 2016

The circled number is 23, but there are only 21 gates. Of course, it doesn't matter since there are no numbered gates, just thought I'd point it out anyway.
Here is the main idea behind this puzzle: <spoiler>First, identify the digits that are in common in all four clues. There are six: 1, 2, 3, 4, 5, 5. Suppose all 6 of these digits appear in the answer. This clearly doesn't work because you have to fill three more spaces, but any digit you add would cause at least one clue to have 7 white dots.

Now just suppose that the final answer contains all digits 1-5 at least once (but only a single "5"). This already accounts for 5 of the white dots for each clue. There is still no way you can get to a 9-digit answer now without hitting at least 7 white dots on one of the clues. (You need to add either a "2" or a "3" because of the last clue, and you can add a single "4", but then you are stuck.)

Since using all five digits can't work, figure out which digit can't possibly appear in the final answer, and once you've done that, you can determine how many of each of the other four digits there must be. Then ordering the digits in the final answer is pretty straightforward.
</spoiler>
Number: Puzzle #5193
Genre: Easy as ABC
Author: Johan
Appeared at: January 30, 2016

Nice design and solving flow!
I have the same problem (in HTML5). However, this puzzle looks right in Java.

d3s wrote:

anurag.sahay wrote:
right,the opening lies in the (1,1)-2-3 region.

No, it does not. This puzzle requires trial & error and it definitely is a 2 star.

Out of curiosity, I just did this one again. The bottom left (1,3)-(1,2) region is where I started, then that forces the rest. Maybe it's not the most obvious opening, but trial & error is not needed. It's a low 2* which seems appropriate.
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