Puzzles #671 & #672 - 24HPC Extras (Slitherlink, Sukoro)

I made two puzzles for the 2024 24 Hour Puzzle Championship that went unused, one for each round. I made a Slitherlink for Epsilon in the Greek round, but we went with djmathman's massive Numberlink instead, to be funny.

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I also made a Sukoro (also known as Infection) for the Cancer slot when it was empty. I said I was going to do so the next day, went to go to sleep, couldn't sleep, checked the sheet and chat, saw it was still empty, and made this puzzle. I go to post it and someone else posted a Cancer slot Tren in the time this took to make, and since I had a bunch of puzzles in the rounds already, the Tren was used instead. I really like this puzzle though, I'd never tried to make a Sukoro before and you also don't usually see clue layouts this dense for it.

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Puzzles #668, #669 & #670 - 24HPC Zodiac (Little Killer Latin Square, Antiknight Tomtom)

I also contributed several puzzles to the Puzzlers Club rounds at the 2024 24 Hour Puzzle Championship this year. We authored two rounds, each with 24 puzzles. The first round had one puzzle themed on each Greek letter, while the second round was a double zodiac (signs and animals).

The other half of this round was themed on the Chinese zodiac animals. Rat went unclaimed for a long, long time, so I elected to make a puzzle using the Little Killer sudoku variant rule. Rather than make a sudoku and deal with regions and larger grids or irregular regions, I went with just a Latin Square. Here's a quick example puzzle I also made for the instructions booklet: the rules are pretty straightforward. Place a number from 1 to N (where N is the side length of the grid) into every cell, so that there are no repeats in a row or column. Arrows outside the grid give the sum of all the numbers inside the grid that they point to.

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And the actual competition puzzle, worth 20 points. I tried to make it really tricky, but ended up missing a case so the logic is really messy and honestly the cleanest way is just a bifurcation, unfortunately. It's still unique and still a puzzle I made, so here it is.

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I also claimed the spot for Horse with an Anti-Knight Tomtom; like with the IPC Killer Doppelblock, I didn't know which genre I wanted to use beyond a latin square type, but Tomtom quickly proved its worth and potential for some crazy theming. I ran into so many dead ends from only a few cages in this construction and it was really painful, even with using f-puzzles to help speed through "easy" anti-knight steps. The final puzzle is actually unique without the 21 cage, but since it's worth 110 points with the extra clue... yeah I think it's necessary for a good puzzle. Reminder everyone, harder/minimal cluing is not always better.

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Puzzles #665, #666 & #667 - 24HPC Zodiac (NIKOJI, Nurimisaki, Balance Loop)

I also contributed several puzzles to the Puzzlers Club rounds at the 2024 24 Hour Puzzle Championship this year. We authored two rounds, each with 24 puzzles. The first round had one puzzle themed on each Greek letter, while the second round was a double zodiac (signs and animals).

Even though I've already done a Puzzle Zodiac before and wasn't too enthused by this theme, I still made 3 puzzles for the zodiac signs side of things. NIKOJI is otherwise known as Gemini Block, which was a type I was unaware of at the time of my original Puzzle Zodiac. The bottom row not being a word was kind of annoying, but I tried using Qat to find any words that could work and none existed. This was worth 30 points in the round.

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Cats like to curl up in corners. Nurimisaki is a type all about corners. It's a bit of a stretch but I like the genre and had originally thought of the type for PZ, even though I went with Akari at the time. I checked with some solver assistance to see if there was any way of avoiding the extra circle in the top left corner and unfortunately found that it was impossible to specify that corner without another clue. Puzzle is worth 25 points.

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To round out the comparison, I grabbed Libra to make a Balance Loop worth 50 points. This was one of the biggest missed opportunities of the original PZ in the name of genre balance, and while I don't regret my old choice of Minarism... this Balance Loop is way, way better. I did have a working version without that center clue at one point, but this required neutering a lot of the logic in the second half of the solve, so I sacrificed the purity of the theming for the sake of a much better puzzle. In general I skewed a bit larger on grid size this 24HPC to try to prevent undershooting round length again, and as a whole we succeeded -  the rounds were maybe a bit oversized, but well within acceptable ranges for the 24HPC as a whole.

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Puzzle #664 - 24HPC Ripple Effect

I also contributed several puzzles to the Puzzlers Club rounds at the 2024 24 Hour Puzzle Championship this year. We authored two rounds, each with 24 puzzles. The first round had one puzzle themed on each Greek letter, while the second round was a double zodiac (signs and animals).

As construction was wrapping up there were a few missing Greek letters. None of the puzzles so far used the grid shape for the theme, and Ripple Effect is always a fun type to do on irregular grids. This puzzle ended up being only worth 25 points which is a bit lower than I would have expected, but I guess most of the solve path is pretty straightforward, and even though it's "10x10" there is a lot of empty space.

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Puzzles #662 & #663 - 24HPC Loops (Nagare, All or Nothing)

I also contributed several puzzles to the Puzzlers Club rounds at the 2024 24 Hour Puzzle Championship this year. We authored two rounds, each with 24 puzzles. The first round had one puzzle themed on each Greek letter, while the second round was a double zodiac (signs and animals).

I don't remember why Psi got a Nagare puzzle. My notes apparently say it's a play on wind/pressure/Pounds per Square Inch/PSI/psi, but that's a huge stretch. Despite the size, this one is only worth 25 points, because the type is honestly pretty tame and hard to make difficult. Can't really complain too much though, as this was a struggle to make work at all honestly.

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For Omega, yyao had made a pretty basic Simple Loop with a note to replace the slot in the case of a better puzzle. I thought All or Nothing would be a pretty fitting genre and had even written it down as an idea locally, so as construction was wrapping up and the round was tending a bit easier than desired, I made one to finish off the Greek round. I still have one puzzle left to share from the round, though...

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Puzzles #660 & #661 - More 24HPC Shading (Light and Shadow, Aquarium)

I also contributed several puzzles to the Puzzlers Club rounds at the 2024 24 Hour Puzzle Championship this year. We authored two rounds, each with 24 puzzles. The first round had one puzzle themed on each Greek letter, while the second round was a double zodiac (signs and animals).

I made my now-standard Light and Shadow for Lambda, after some research into what lambda was usually used to represent. Turns out it's often used for light, which provided justification for the genre pick. This one ended up being worth 60 points, which I think is pretty fair for the size. I remember being quite happy that the underside of the lambda was all question marks, which always provide some fun reachability options.

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I also made an Aquarium for Rho with only row clues. Because I thought it would be funny. I did put some consideration into what genre with row/column clues would be a good pick, but nothing else seemed quite as promising. This puzzle tested pretty breezily at only 20 points, which is about what I was aiming for.

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Puzzles #658 & #659 - 24HPC Domino Kurodoko

I also contributed several puzzles to the Puzzlers Club rounds at the 2024 24 Hour Puzzle Championship this year. We authored two rounds, each with 24 puzzles. The first round had one puzzle themed on each Greek letter, while the second round was a double zodiac (signs and animals).

Very early on I grabbed Beta and made a variant Kurodoko where instead of shading single cells, you shade dominoes instead. This variant does result in a bit of struggle for uniquely specifying the orientation, and can also sometimes have long-term propagations that break the puzzle way in advance. I'm pretty happy with how this 40 point puzzle turned out. I also wrote an example for the type, since it wasn't a classic type.

puzz.link interface      penpa interface

puzz.link interface      penpa interface

Puzzles #655, #656 & #657 - IPC Extras (Yajilin, Masyu All Cells)

Like last year, I helped contribute to the Indian Puzzle Championship this year. If you're interested in seeing the rest of the set, including bonus puzzles, check the link for details on how.

I had a couple extra puzzles I made that weren't used for competition - two alternate Yajilin options I didn't offer (since I liked the one that was used to much for the slot), and an All Cells Masyu meant for round 2 - logical optimizers. It didn't fit the round theme that well and there was already a puzzle with a similar vibe, so instead you get it as just an All Cells Masyu puzzle. Yay!

puzz.link interface

puzz.link interface

puzz.link interface      penpa interface

Puzzles #652, #653 & #654 - IPC Round 3 (Killer Doppelblock, Clone Snake)

Like last year, I helped contribute to the Indian Puzzle Championship this year. If you're interested in seeing the rest of the set, including bonus puzzles, check the link for details on how.

Round 3 was themed on taking sudoku variants and applying them to non-sudoku puzzles. I put myself down for number placement, wanting to make a puzzle of a type that has arithmetic normally combined with killer cages. I thought about a few types before settling on Doppelblock. I also signed up for clone Snake since I knew the combination had potential from old, old Islands of Insight rule prototyping. In fact, now that that game isn't getting new content, I know a lot of these old unused puzzles will stay unused, so retain all the rights to them. I've gone through my archive and have about 80 puzzles in this category I think are good enough to share, so at some point I'll have to set up solving interfaces/write rules/share them.

Anyway, Killer Doppelblock! Standard Doppelblock rules apply. Additionally, all the numbers inside a cage add up to the number in the corner of the cage. This is a pretty cool combination, where the different ways of getting partial sums interact in some really cool ways. This was worth 65 points.

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Clone Snake: Standard Snake rules apply, with given endpoints and an unknown length. Two cages of the same shape and orientation must have the same arrangement of snake and not snake cells. The first puzzle here is actually one of those old IOI prototype puzzles, since I added it to the organization sheet after a couple failed constructions, to at least have a puzzle in the slot. I put a note that this was from a couple years ago and I didn't think anyone at the IPC would have seen it before. A few hours later, I finally turned up a satisfactory second puzzle, and added that to the sheet to provide an option for which puzzle to use. Prasanna chose both, worth 30 and 50 points.

penpa interface

penpa interface

Puzzles #649, #650 & #651 - IPC Round 1 (Fivecells, Cave, Yajilin)

Like last year, I helped contribute to the Indian Puzzle Championship this year. If you're interested in seeing the rest of the set, including bonus puzzles, check the link for details on how.

As usual, round 1 revisits puzzle types that appeared in Puzzle Ramayan throughout the year. I contributed 3 puzzles to this round, a 55 point Fivecells, a 30 point Cave, and a 25 point Yajilin.

I had a really tough time settling on a theme for my region division pick, but once I thought of putting pentominoes of clues into the grid, I had to run with it. It was a small step from there to try pentominoes of only 3s, and some initial steps proved quite workable and interesting, so I kept pushing at that idea until I had a finished puzzle. I'm a bit sad about the diagonal touching, but there was no way around it and the theme is still quite clear.

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Cave was an option. I like Cave. I'm good at making Caves. So for some reason I tried to find a valid, interesting puzzle with this layout, and suffered for hours with multiple very close attempts that were a single ambiguous cell away. I also didn't start from this full layout, just one half with a cool opening, and eventually tried for the full symmetry after finding no good continuation.

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Originally I had just claimed two spots in round 1, but the evergreens category remained empty as the deadline approached. So I made a Yajilin for the slot, didn't like it, made another Yajilin for the spot, thought it was a bit rough in the middle, and made yet another for the spot, which is this puzzle. This is a pretty slick layout I think, the bigger tilted square works really well for Yajilin.

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