[HN Gopher] Calendar Puzzle "Rhombus"
       ___________________________________________________________________
        
       Calendar Puzzle "Rhombus"
        
       Author : xyzzy_plugh
       Score  : 55 points
       Date   : 2025-10-12 15:29 UTC (9 days ago)
        
 (HTM) web link (praxispuzzles.com)
 (TXT) w3m dump (praxispuzzles.com)
        
       | rawling wrote:
       | Have they made it so impossible dates are impossible, I wonder?
        
         | xyzzy_plugh wrote:
         | Doesn't seem like it. Using the interactive board on the
         | website I was able to produce a solution that only revealed
         | numbers.
        
         | peterpuzzle wrote:
         | Creator here. No, you can arrange the puzzle pieces to make
         | dates that don't exist, like Monday February 31. Actually there
         | may be "impossible" dates, because I didn't check for them, but
         | I guess all combinations of days of the week, day of the month
         | and month are possible. And also many non-dates, like 1, 2, 3.
         | But good point: alle possible dates have at least 1 solution.
         | Disclaimer: I sell these puzzles for a little more than the raw
         | material.
        
           | seanhunter wrote:
           | Looks like a really nice puzzle. Congrats.
        
           | legedemon wrote:
           | Great puzzle. Do you ship internationally?
        
             | yapyap wrote:
             | not OP but yes
        
           | slig wrote:
           | So nice! Do you create them entirely algorithmically, or do
           | you use the solver just to verify that every date is
           | possible?
        
             | peterpuzzle wrote:
             | I wrote 2 solvers in Python. One that loops through all
             | possible dates and searches for a solution. And one that
             | loops through all solutions and checks if they form a date
             | or not. And luckily both gave the same answers.
        
               | drivebyhooting wrote:
               | How did you select the piece shapes to ensure there was
               | always a solution?
        
               | peterpuzzle wrote:
               | Actually I tried a lot of different combinations of piece
               | shapes to find the "hardest" set of pieces that can still
               | solve all possible dates. "Hard" is subjective, but I
               | mean pieces with multiple protrusions.
        
       | zvr wrote:
       | I have the "A Puzzle A Day"
       | https://www.dragonfjord.com/product/a-puzzle-a-day/ since a few
       | years and I have thoroughly enjoyed it.
       | 
       | All dates are possible and most (all?) have multiple solutions.
        
         | spencerflem wrote:
         | Was just about to link to this one!
        
         | peterpuzzle wrote:
         | Creator here. That puzzle started my search into this type of
         | puzzle. But in the end my puzzle is harder, because it also
         | contains the day of the week and has the most "irregular"
         | puzzle pieces possible.
        
       | Y_Y wrote:
       | Those particular rhombuses are typically known as "squares"
        
         | dfee wrote:
         | I thought the same thing, but it seems that certain dates would
         | make it so there is one square ("rhombus") and one (non-square)
         | rectangle (e.g. Feb 15).
         | 
         | So rather than 3 rhombuses - or 3 squares - perhaps it's 3
         | squares of 1 square and 1 rectangle. (Perhaps the positions of
         | the puzzle pieces make it such that it truly is 3 squares)!
        
         | RyanOD wrote:
         | Announcing new Diamond Shreddies!
         | 
         | https://www.youtube.com/watch?v=bccNH82DIo0
         | 
         | https://www.youtube.com/watch?v=hF_2yHXD_CU
         | 
         | (and...neat puzzle...nice job, creator!)
        
         | peterpuzzle wrote:
         | Creator here. I know, I know, the "rhombuses" are just rotated
         | "squares", but I already had a calendar puzzle "Square", so
         | that's why.
        
       | ky_vulnerable wrote:
       | That's really creative. Did the creator come up with the design
       | himself?
        
         | peterpuzzle wrote:
         | Creator here. Yes I did. Used some existing puzzles as
         | inspiration. See
         | https://praxispuzzles.com/calendar_puzzle_square
        
       | seszett wrote:
       | Nice, but it's only available in English sadly, there's a link
       | that says "see kalenderpuzzel "Ruit" for the Dutch version" (I'd
       | prefer French but Dutch would do as well) but that page says "De
       | maanden en dagen van de week zijn in het Engels".
       | 
       | The "square" one is in Dutch but sold out and the Rotterdam one
       | in English only.
       | 
       | But I like that idea, apparently it's not the first puzzle of
       | this kind but I didn't know about them.
        
         | peterpuzzle wrote:
         | Creator here. If there is enough demand I can make a French
         | version. Ordering a new batch of lasercut wood cost me $20, so
         | I have a minimum batch size of 20.
        
       | nonethewiser wrote:
       | Seems pretty hard! Even the easy example.
        
         | peterpuzzle wrote:
         | Creator here. I sometimes advise people not to focus on today's
         | date, but a date in the following week. Then you have more time
         | to find a solution!
        
       | racl101 wrote:
       | Ooh, nice white elephant gift idea for work. I never know what to
       | give.
        
       ___________________________________________________________________
       (page generated 2025-10-21 23:01 UTC)