[HN Gopher] The Flummoxagon
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       The Flummoxagon
        
       Author : robinhouston
       Score  : 107 points
       Date   : 2025-10-07 15:40 UTC (5 days ago)
        
 (HTM) web link (n-e-r-v-o-u-s.com)
 (TXT) w3m dump (n-e-r-v-o-u-s.com)
        
       | fjfaase wrote:
       | Nice article, which also explains the mapping of the puzzle to an
       | exact cover problem and how those can be solved with dangling
       | links as in Knuth's Algorithm X.
        
         | MontagFTB wrote:
         | A blast from the past! I once wrote an implementation of
         | dancing_links in C++ as part of a Sudoku solver:
         | https://github.com/stlab/adobe_source_libraries/blob/main/ad...
        
       | jeffrallen wrote:
       | Oh my god, take my money, please. These types of tactile puzzles
       | are the ideal nerdsnipe for me.
        
       | colordrops wrote:
       | Looks amazing but getting 500 errors from the payment flow and
       | the FLUMMOX discount code doesn't work as advertised.
        
         | nervous_jessica wrote:
         | hi colordrops! the flummox coupon works in the shopping cart.
         | often folks try to apply it in the gift card box in the
         | checkout procedure. Let me know if you already placed and order
         | and I can apply the coupon retroactively for you. If you would
         | like to provide any more info on the checkout errors you can
         | email me at orders@nervo.us
        
           | phinnaeus wrote:
           | As an aside, nervo.us is way easier to type than the
           | hyphenated domain. Just curious if you ever considered
           | reversing the redirect?
        
             | nervous_jessica wrote:
             | I'm somewhat ignorant about the search ranking implications
             | of changing our domain. I bought the nervo.us domain much
             | later and we've had the n-e-r-v-o-u-s.com domain since
             | 2007.
        
         | mannykannot wrote:
         | I paused at the statement "Add $55 for free domestic shipping"
         | on the order form.
        
       | smokel wrote:
       | Very interesting, but I have a hard time differentiating the
       | colors. The gradients seem to be there for aesthetics only, but
       | they confuse me to no end :)
        
         | nervous_jessica wrote:
         | Fair point. The gradients are just to be pretty. We could make
         | you a solid color version if you would like. Email
         | orders@nervo.us and we can set up a custom order.
        
       | cadamsdotcom wrote:
       | Absolutely love this. Amazing creativity!
       | 
       | Totally feeling like vibe-coding a web version of the game and
       | plastering it with giant BUY THIS THING links that send people to
       | the real thing.
        
       | rendaw wrote:
       | Tangential, but does anyone know good places to find other
       | physical puzzles like this? Also, recently there was an article
       | on elastic knots I was hoping someone would productize into a
       | novelty puzzle.
        
         | robinhouston wrote:
         | Be careful! There's a whole world of mechanical puzzles out
         | there, and it can get very expensive and start to take over
         | your life.
         | 
         | Here's an assortment of links to places where you can buy
         | interesting puzzles. This isn't exhaustive of course: it's just
         | a few places that came to mind.
         | 
         | https://www.puzzlemaster.ca/
         | 
         | https://puzzleparadise.net/
         | 
         | https://www.pelikanpuzzles.eu/
         | 
         | https://twobrassmonkeys.com/
         | 
         | https://www.etsy.com/shop/PuzzleguyStore
        
           | jonahx wrote:
           | Also:
           | 
           | Tavern Puzzles, high quality metal entanglement puzzles:
           | 
           | https://tavernpuzzles.store.turbify.net/puzzle.html
           | 
           | Craighill. These puzzles are beautiful and double as art
           | objects:
           | 
           | https://craighill.co/collections/play
        
       | MontyCarloHall wrote:
       | So many puzzles like this basically require you to brute-force
       | the solution [0], which just isn't all that fun. I'm glad the
       | designers explicitly acknowledge they're trying to avoid this,
       | and really hope that their claim that this actually can be solved
       | with logic holds true:                  What if instead of doing
       | the full colored puzzle, we find partial sets of tiles where
       | there is only one unique solution? This adds enough constraints
       | to the problem that it becomes feasible [without resorting to
       | brute force].
       | 
       | [0]
       | https://www.puzzlemaster.ca/search/?c=woodpacking%2Cwoodtang...
        
       | peterpuzzle wrote:
       | Recently I designed a calendar puzzle with 10 tetris-like pieces.
       | When you place all the puzzle pieces on the board, three
       | squares/rhombuses are still open and together they form a date.
       | Can you arrange the puzzle pieces in such a way that it shows
       | todays date? See
       | https://praxispuzzles.com/calendar_puzzle_rhombus Disclaimer: I
       | sell these puzzles for a little more than the raw material.
        
         | xyzzy_plugh wrote:
         | This is quite clever.
        
         | teraflop wrote:
         | Very cool!
         | 
         | Unfortunately the interactive demo doesn't work for me (Firefox
         | 143.0.4 on Windows):
         | 
         | > Uncaught TypeError: can't access property "inverse",
         | this.puzzlemat.getScreenCTM() is null
        
         | rawling wrote:
         | Can you arrange them to make dates that don't exist, or is it
         | designed so you can't?
        
       | phinnaeus wrote:
       | Love Nervous System design. I have quite a few pieces from them
       | including one of their infinity puzzles. Very high quality work.
        
       | tromp wrote:
       | Reminds me of the 1 million pound first solution prize Eternity
       | puzzle ...
       | 
       | https://en.wikipedia.org/wiki/Eternity_puzzle
        
       | fjfaase wrote:
       | It would be nice, if they could publish the exact cover. I have
       | written some algorithm that can estimate the number of solutions
       | to an exact cover base on the number of solutions it found and
       | the size of the 'tree' that has been explored.
       | 
       | I could write a program myself to calculate the exact cover, but
       | I guess, it will take me about a day to do so. It would not
       | surprise me if the exact cover will be a few hundred mega bytes
       | (when using one character per position).
        
         | nervous_jessica wrote:
         | We haven't actually run the thing to completion. We ran it for
         | a couple days and then stopped after finding tens of thousands
         | of solutions. Might explore again if we have time to improve
         | the solver efficiency.
        
       | amiga386 wrote:
       | https://www.chiark.greenend.org.uk/~sgtatham/puzzles/js/map....
        
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       (page generated 2025-10-12 23:01 UTC)