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Showing posts from December, 2025

#A73: Shikaku and Knossos

 I've solved a few of each genre before today, but this is my first time constructing either, despite the fact that the former is relatively well-established. I find that Shikaku tends to flow quickly due to how the anchored rectangles need to fill the space, making it difficult to set a hard one, whereas Knossos tends to flow slowly due to how unconstrained the clues seem without considering theory, making it difficult to set an easy one. I admire how different they feel to solve despite considering two fundamental aspects that correlate with region size, although maybe this is due to Knossos not being about rectangles. Geometrically speaking, I would've preferred if these puzzles were assigned tomorrow and tomorrow's puzzles were assigned today. 23, unlike 24, cannot be a base Knossos clue. Furthermore, 24 is highly divisible, whereas 23 is a decently large prime, making 24 versatile and 23 unwieldy as a Shikaku clue. The cherry on top is that 12x23 happens to be a triang...

#A72: City Space

 This genre reminds me of Cave from its clues, Nuribou from its block styles (Ca-ribou?), and Guide Arrow from the unshaded constraint. The combination of forcing shaded squares in areas with lots of unshaded squares and further forcing each shaded square to be in a rectangle with an area of at least 2 causes this genre to be explosive at times, though this does permit some interesting connectivity logic with the shaded masses as a whole. https://pzprxs.vercel.app/p?cityspace/5/5/2i2p2l5h https://pzprxs.vercel.app/p?cityspace/12/12/2j2i2ncg-16zx2zj5zi5t2g5w5 https://pzprxs.vercel.app/p?cityspace/12/22/i5j2i2p5j.h.zz2p2gch-16h-14h-19u5l.zl5p2zj5p2zzn.p..p./

#A71: Castle Wall and Castle Walker

 I've done advent puzzles for Castle Wall before, but Castle Walker is new to me. I don't think it's a true Walk genre, but I admire how all the clues are recontextualized to let the loop pass through the clues instead of around them. I've included a doppelganger to demonstrate how they can resemble each other visually but not logically. https://pzprxs.vercel.app/p?castle/5/5/021022a022021g030d040g https://pzprxs.vercel.app/p?castle/12/12/d031b042h032b041zb011012c212211c012011n042f210d022f235o242b010b012b015b212h035d042d02.c https://pzprxs.vercel.app/p?castle/5/5/b20.b243g10.d132b20.c Puzzle Square JP genre page (contains rules and example) Castle Walker 5x5 (Castle Wall Doppelganger) Castle Walker 12x21

#A70: Number City

 This genre can be compared to Tile City beyond semantics due to its incremental structure, but every aspect makes Number City less rigid, from the input type to carving the board yourself. In spite of this, the ruleset is tailored such that puzzles typically don't feel too loose. I especially like how the border rule is used in the context of this genre. https://pzprxs.vercel.app/p?numcity/5/5/r4r9ttiig8e https://pzprxs.vercel.app/p?numcity/12/12/l1l12p2j3i22m3zm3r5j21i3u2l2m5i25i2h3l2412rh08g48e412oh08g4be412000h0480fvsg040g05vvg08g2400 https://pzprxs.vercel.app/p?numcity/12/20/7-127k5efat-12t5n9zmc-10k7y1h1ic-14q-1425i1zn6bs1zg-114zmdg6b3dl4g0000000000000000000co9i36000000000000000000000000000000000000022198aa110000000000000000000

#A69: Tile City

 I suspect that this genre is meant to be set with global ideas in mind more often than local ideas. Most of the rules set constraints on what sizes of regions are allowed to connect to each other, and the "no two by two" rule could be thought of as necessary to prevent a maximally shaded grid. https://pzprxs.vercel.app/p?tilecity/5/5/pv7taa66y https://pzprxs.vercel.app/p?tilecity/12/12/qptr7nf6pahfrrdnv5nptvjebe8f5aqaqivvttsvmmsvvbkoau2fpgb2zzzx9zl https://pzprxs.vercel.app/p?tilecity/12/19/18fufufvi3t3srj6rudh313cf3c3rirvrsnstv4400avg0o06agro6cfhf4dmv5tpeephf4vh0ii5p340povv0zzzzzzzzt

#A68: Windows

 This genre feels like a mashup of several popular constraints from other genres, which makes it feel tight both to set and solve. I much prefer the Kudamono expansion of the base ruleset because it allows for regions of different shapes and sizes: I was reminded of Sudoku and how it's universally agreed that irregular boxes are a Sudoku variant, even though that and this are the only two puzzle genres I can think of that require a specific region layout in order to be a classic puzzle. That being said, the suggested layout does lead to neat patterns. https://pedros.works/paper-puzzle-player?W=5x5&L=b0&SIE=6UUUUU6UUUUU14DLUR2LDRU&G=windows&D=2025-12-18 https://pedros.works/paper-puzzle-player?W=12x12&L=b2b41b25b11b34b21b8&SIE=3RRRUUURRRRRRUUURRR3RRRUUURRRUUU3RRRUUU30UUURRRDDD78UUULLLUUUUUURRRUUU45LLLDDDRRR&G=windows&D=2025-12-18 https://pedros.works/paper-puzzle-player?W=12x18&L=b2b6b4b5b7b8b6b4b24b11b6b23b17b5b3b2b5b9b5b2b4b5b19b3b24b4&SIE=2...

#A67: Building Walk and Skyscrapers

 Despite having "Walk" in its name, I don't think Building Walk is canonically a walk type. I find it especially impressive that this genre has automatic answer checking given how abstract the elevator sequences can be. https://pzprxs.vercel.app/p?bdwalk/m/5/5/15512g3j..h2g8h..j3g6 https://pzprxs.vercel.app/p?bdwalk/m/5/5/22441g0001i013.601i01i0 https://pzprxs.vercel.app/p?bdwalk/m/12/17/11c-11o2g2p2h.3232g.i2h2i2i2i3i3m2i2i.i32323i2p.zzzt3n.i3g3g.3h.h3g3o I usually find Skyscrapers difficult to set because the available clues are either only usable in certain circumstances or initially loose, but this does often lead to clues staying relevant throughout the solving process. https://pzprxs.vercel.app/p?skyscrapers/5/5/h1g5g2j22g5k I also tried making a 12x12 mashup of today's genres, but I wasn't able to get it to work.

#A66: Nuritwin

 I'm a bit cynical over the potential for difficult logic in Kuroclone, and I think some of those feelings might've transferred over to my first impressions of Nuritwin. However, I ended up enjoying Nuritwin because the connectivity and packing logic help create reasons for block sizes to be above or below certain amounts even in the absence of numbers. https://pedros.works/paper-puzzle-player?W=8x8&L=(2)4(2)3(5)16(6)16&SIE=1RUUUL4RR22ULUUUUUUU9UUUUUUUU12RDR19DDDLLUUURR1ULU9LLLUURRR&G=nuritwin&D=2025-12-16 https://pedros.works/paper-puzzle-player?W=12x12&L=(3)4(2)15(3)57&SIE=3RRRRUU2RUUU3RRRURRRUUU1RUUU9RRUU4RRUUU17UUU5RRUU8UUU13UUUUU13UUUUU7DDRRRUUUU2DDLLLU1RRR29UUUU7RRUULLUUU19UUU6DDLLU10LU3LU3LUUU&G=nuritwin&D=2025-12-16 https://pedros.works/paper-puzzle-player?W=12x16&L=(5)6(2)5(12)4(4)27(6)14(6)31(2)32(3)15(16)57&SIE=7RR2RR2RRRRR1RRRRRRRRUUUU22UUUUUUUUUUU17UUUUUUUUU34UUUUUUUU9LLUU3DDDDRRRRRRR22UUUUUUU3RRDRUUURR48UURR4LLUUU37LLLLLU...

#A65: Tetrochain (CTB, Y, and K)

 I remember Tetrochain-Y as the O.G. Tetrochain. It's cool that this genre has the distinction of having other official genres with the same shading constraints under different clue types, instead of just as special variants of one puzzle. If I had to guess, CTB likely stands for "Cross The Borders", Y for "Yajilin", and K for "Kurarin".  I initially underestimated the border-crossing rule in CTB: it turned out to be rather versatile. It can establish tighter minimal number logic for large regions and tighter maximal number logic for small regions, but also helps restrict flow in large regions. https://pedros.works/paper-puzzle-player?W=5x5&L=(6)9(5)5&SIE=6UUUUU6URRULLUUU22LLDRR&G=tetrochain-ctb&D=2025-12-15 https://pedros.works/paper-puzzle-player?W=12x12&L=(4)1(5)2(2)4(9)4(2)40(3)4(2)4(1)20(6)4(3)6(2)10(5)6&SIE=2RRRR2RRRRDDDD4RRRRRRRRRRRR50RUR20UUUUULU5RU21UUUUUUUUUUUU6LULUUUUU4RRRR46LLLLLLLLUUUUUUUU&G=tetrochain-ctb&D...

#A64: Shakashaka

 Since I regretted not doing so last time, this time I've tried to include some large rectangles. https://pzprxs.vercel.app/p?shakashaka/9/9/zgbcgdzgdgbey https://pzprxs.vercel.app/p?shakashaka/12/12/.k..i2.sbjcrbnbzhbncrcjeq1.i.ci./ https://pzprxs.vercel.app/p?shakashaka/12/14/g.i1bg.ubjcr..n..cnczhcn2..n..tbjes.i1bg.g

#A63: Energy Walk

 This genre feels like Forest Walk on steroids. Deductions aptly tend to be powerful. The rule about energy cells not being allowed to connect directly to themselves tends to be useful for disambiguation but also makes it more difficult than it already can be to tie off loose ends. Psychic Energy Walk (5x5) https://pzprxs.vercel.app/p?energywalk/12/13/001g0cs0521o0001sv94a92u8g3s0000idztczpdds-19zzzq https://pzprxs.vercel.app/p?energywalk/12/12/00at0h05o18ibg02sih05o121bk00ici.h6r6z.tdwczzh6r6ldi

#A62: Kurarin and Sansa Road

 This was the day on the advent calendar I was most looking forward to. This style of dot cluing is a nice and concise way to introduce dense set logic into loop puzzles. It surprised me when I noticed today that Sansa Road was invented before Kurarin, since Kurarin seems like the simpler of the two genres and was the first to be officially added to the pzprxs editor, though I suppose that could explain why Kurarin uses shaded squares. I also like how Sansa Road incorporates the cell-loop logic of Nurimisaki with clues that allow for a controlled flow. https://pzprxs.vercel.app/p?kurarin/5/5/k88ncg8kc8cmcm https://pzprxs.vercel.app/p?kurarin/12/12/s8hc4w84j8g82t8ich8u4h4i888rc48g884zzj8hc8s888gc8j4t8h8i4s2g8h8hcxc8cgc44r https://pzprxs.vercel.app/p?sansaroad/7/7/r8i4i8g8u8m8ucg8i4i4r https://pzprxs.vercel.app/p?sansaroad/12/12/h2w8cczw4222h4w8g8g8k2k2s8n2l8g8g8k2k2i8r2k2l8g8g8w422g2zycc8v2i

Perfect Production & Foundational Implications

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(last updated on the same day to add an example for the first type)  On rare occasions, a dream of mine can end with cracking open a puzzle book and finding something I don't recognize as an existing genre. If I'm lucky like I was last night, then I might be able to leaf through a few pages and glance at multiple examples of clue types and suggested input types. Then when I wake up, it becomes an interesting challenge to try to invent a fun ruleset that could apply to anything I can remember. The fact that I can only barely remember certain aspects makes it more lateral than instructionless puzzles typically are. This first type was inspired by a puzzle I thought allowed multiple loops with really large numbers as clues, but I specifically remember looking at some of the lengths of rows used by a portion of the grid to verify that they were factors of the number in the portion. Since I decided to go for an edge input instead, the end result feels like Lohkous, but I think the l...

#A61: Balloon Box (Revised)

 This genre reminds me a bit of Pencils but might be closer to Shikaku. It's interesting how it tries to counterbalance the relatively rigid logic in the shaded cells with the relatively loose logic in the unshaded cells.  In addition to not knowing what the original ruleset was before the revision, I'm also not entirely certain what the current ruleset is supposed to be. The default pzprxs implementation differs from the Puzzle Square JP rule tab in that a numberless looped string is valid, but enabling the "Strings cannot loop back on themselves" checkbox also differs because it causes a string that passes next to itself to be invalid. The shared example solution isn't open enough to differentiate and all three versions of the ruleset pose different kinds of nuance. The following puzzles use the version of the rules where strings may snake near themselves but loops aren't allowed. https://pzprxs.vercel.app/p?balloon/v:/a/5/5/hphjhg12n1g1n25g https://pzprxs.v...

#A60: Statue Park

 I believe this is the first genre for which I've already given my thoughts in a previous year's advent series. I've decided to skip the introduction in this case unless I think I have something new to add. https://pzprxs.vercel.app/p?statuepark/5/5/005901060/2/13s/32pg https://pzprxs.vercel.app/p?statuepark/12/10/000060i00007i06503500f60f301l00001030000/8/13s/33p6/13s/23vg/33p6/23vg/33p6/33dc https://pzprxs.vercel.app/p?statuepark/12/12/006j3g00626a3g026i6j3g0000alk3k600a3j3k606alk300//p Variant: Get 5 simultaneous errors. (This requires enabling "Check multiple errors" in the "Setting" tab.) https://pzprxs.vercel.app/p?statuepark/v:/4/3/0020/2/13s/22u

#A59: Forest Walk

 The use of a network instead of a loop invites more theory related to connectivity. https://pzprxs.vercel.app/p?forestwalk/5/5/8i81g1g2o9r https://pzprxs.vercel.app/p?forestwalk/12/9/el0011a902ak2040900o04l9i9g9n9p9j9zn9r9r9u https://pzprxs.vercel.app/p?forestwalk/12/12/gsb8k29422vmh4c92rugg94ga5ke2u2k2i1i9v.h5x9l5x9h2v9i.i.k5u

#A58: Ripple Effect and Shimaguni

 Ripple Effect is an accurate description of both the joy of solving it and the pain of setting it. Every aspect of the grid feels strongly connected. https://pzprxs.vercel.app/p?ripple/5/5/932ro7uaj8g45g6j5p Shimaguni can be compared to Ripple Effect because the logic for both is typically dependent on the sizes and arrangement of the regions, but Shimaguni is relatively easier to set because the constraints that apply within a region require less information to resolve. https://pzprxs.vercel.app/p?shimaguni/5/5/pj1ig0e1128h https://pzprxs.vercel.app/p?shimaguni/12/12/si4vufvjptvuvi914husf4noi90j4k00610o80glknvvips6dgud7gh2cg7l4645l https://pzprxs.vercel.app/p?shimaguni/12/8/ab55lcqmdb6liqldak00vvg0s9g1g7gu000zg

#A57: Hashiwokakero and Key West

I get the impression that Hashi is a well-known genre despite rarely being set online. I suspect this is because the looseness of its set-based logic alludes to puzzles like Minesweeper but also requires lots of clues, which makes it difficult to construct a hard one without having an idea in mind for the grid as a whole. https://pzprxs.vercel.app/p?hashi/5/5/33.3.12g73.i.32g25.3.33 https://pzprxs.vercel.app/p?hashi/12/7/g2i.5h22.22h.h2i2g2k2i.g.j5i2h5i5j2h2h2j.h222g2222g2h https://pzprxs.vercel.app/p?hashi/7/7/1g3g3g3m3g2g2g3m2g1g.g5m3g2g3g3 Key West reminds me more of Sukoro than Hashi. It flows decently well while setting and solving by merit of being both tighter than Hashi and looser than Sukoro.  https://pzprxs.vercel.app/p?keywest/5/5/7ajaam5b https://pzprxs.vercel.app/p?keywest/12/12/k1chb1ahbhabcbi06bcg0bh21eiaj2bidh613eh23aeddcdeci53b43clbi

#A56: Aquarium

 Aquarium reminds me of Tilepaint, at least on the horizontal axis, but it's especially interesting how the directionality of this genre makes it feel a bit like two puzzles in one. https://pedros.works/paper-puzzle-player?W=5x5&LEX=(2)1(1)1(1)4(2)2&SIE=9RDRUULLDL3UULL4U6RDDR4DLU&G=aquarium&D=2025-12-06 https://pedros.works/paper-puzzle-player?W=12x6&LEX=(6)0(6)1(6)1(6)1(6)1(6)1(1)12(2)2&SIE=2R1R1RDDDL1RU13RRR1RR2ULUUUUU1R6UUURURULLU16RRR5ULLURURUUU1RR4RR9UUUUUU17DDLUUR9LLDRR&G=aquarium&D=2025-12-06 https://pedros.works/paper-puzzle-player?W=12x12&LEX=(6)0(5)1(7)1(7)1(6)1(8)1(3)1(7)1(7)1(7)3(8)2(5)8(6)4(6)10&SIE=3RRULL2RRRDDDLLDRRD2RUUUUL24ULURUUUUU2RUUURRULLU7U4RRRDDDDD2RRRULLURRUUU20LUUURDDD4ULU12RRDLL1RRRDDDLLDRRD2RRUUUUU24ULU2RRRUUULLURRU8RRDLL3RRR17DLUR9ULU2R10LLDRR&G=aquarium&D=2025-12-06

#A55: Water Walk

 This genre is one of if not the first to be invented of the Walk family. Compared to the rest, I think it has the loosest restriction on the tiles, but this especially helps it explore the logical capabilities of the number clues. https://pzprxs.vercel.app/p?waterwalk/5/5/9vpc21g2o5o2g5 https://pzprxs.vercel.app/p?waterwalk/12/5/bhq48n3l05e7h2i5k2i2i2g1m2k2g1h2i5p5i https://pzprxs.vercel.app/p?waterwalk/12/12/u3m0jpnc14204t1e80g71tj6c1n0cjch-19i1h2l1s1o11zzk5i2t2j1m5l2r

#A54: Country Road

 The rule about borders and unused cells is really useful but not overbearing. It balances the difficulty of forcing the loop to travel a certain way within a region in the case of a relatively narrow or small region. https://pzprxs.vercel.app/p?country/5/5/p9444sf812g4g https://pzprxs.vercel.app/p?country/5/5/0ne06om8c4h https://pzprxs.vercel.app/p?country/12/4/qrrdtjili407vu2301i1h1g2g14i https://pzprxs.vercel.app/p?country/8/6/aikl59aag03vg1vo0g1g2g44g1g2g https://pzprxs.vercel.app/p?country/12/12/po9ueffjnjj4gl914refn44il9867pgsn01jituvvpg9d0knaq6608k4i42l5g4j5344h I underestimated the included variant at first. In addition to loosening the grid connectivity requirements, it also allows for pockets that influence larger regions. https://pzprxs.vercel.app/p?country/e/12/7/4i293tou9fh4q290vvub7gpm3pkuvvop1n

#A53: Tamago Town

 I think the theming is a great way to represent the novel logical idea of this genre. I initially expected the area size constraint to make it feel too tight, but the inclusion of question marks under the base ruleset compensates to make it looser. It also helps that the area size is chosen such that half the grid contains symbols, which is the middle ground between too congested and too open. In all, it manages to flow nicely despite rules requiring one of two combinations of symbol type per region. https://pedros.works/paper-puzzle-player?W=4x3&L=e2c1e3c1e3p1&G=tamago-town&D=2025-12-03 https://pedros.works/paper-puzzle-player?W=6x6&L=p0e1e3c1e1p1y1c2e1y2e11c1p3e1c1e1e3p1&G=tamago-town&D=2025-12-03 https://pedros.works/paper-puzzle-player?W=12x3&L=y0p1y1y6y1y1p1y1y6y1c2y1y5y2c1p1c1y2&G=tamago-town&D=2025-12-03 A fun theme often leads to fun variants. The specific wording of this variant's rule made me chuckle a bit. https://pedros.works/paper-p...

#A52: Yajisan-Sokoban and Exercise

 I'd seen the ruleset of Yajisan-Sokoban before, but I don't recall solving any besides the example in the rules, and this was my first time setting it. I expect the first half of the name to be a reference to Yajisan-Kazusan due to the rule about boxes covering clues, but the second half likely reflects the translation of "warehouse manager" rather than the base mechanics of the well-established sokoban puzzle genre. I found it difficult to set due to a combination of inexperience with genres where objects move in a single direction and an insistence on a tight theme, but both of these are personal reasons, so I don't doubt that this genre has potential for difficult puzzles that combine logic from its inspirations effectively. https://pzprxs.vercel.app/p?yajisoko/5/5/-13h.i.i-18gdi.i.h-15 https://pzprxs.vercel.app/p?yajisoko/5/5/-13-16c-16j.i..j.g.-15b-15-26 https://pzprxs.vercel.app/p?yajisoko/12/2/h-11-17g..-18ch..he-18..g-17-26h Exercise is so obscure that th...

#A51: Morning Walk

 I consider Morning Walk to be relatively difficult amongst the Walks both to set and solve due to how often it requires thinking several steps ahead. These first two were set between midnight and the hour after: https://pzprxs.vercel.app/p?morningwalk/4/3/lpog1g2j1i https://pzprxs.vercel.app/p?morningwalk/5/5/ehl1el1g2u1 For both of the previous two years, I managed to construct a classic 12x1 puzzle on 12/1. This year I had to resort to a variant, which just barely fit the grid. DIY Hemispherical Morning Walk Since the option was built into the editor, I decided to try the full grid variant. It certainly helped with a themed grid that contained large chunks of morning tiles. https://pzprxs.vercel.app/p?morningwalk/f/12/12/002vlhn5t99avvo01vvj9jrviofvuzxcj1i2zk3k2i1s1zi1h1k4s After setting the previous puzzle, I felt confident enough to try setting a puzzle in which the morning tiles are placed with a logical theme in mind. I'm happy with how it turned out. https://pzprxs.vercel.a...