Calendar Puzzle "Rhombus"

53 pointsposted 9 days ago
by xyzzy_plugh
(praxispuzzles.com)

19 Comments

seszett

7 hours ago

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.

racl101

5 hours ago

Ooh, nice white elephant gift idea for work. I never know what to give.

rawling

9 days ago

Have they made it so impossible dates are impossible, I wonder?

peterpuzzle

11 hours ago

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.

slig

9 hours ago

So nice! Do you create them entirely algorithmically, or do you use the solver just to verify that every date is possible?

peterpuzzle

8 hours ago

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

6 hours ago

How did you select the piece shapes to ensure there was always a solution?

peterpuzzle

4 hours ago

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.

seanhunter

9 hours ago

Looks like a really nice puzzle. Congrats.

legedemon

9 hours ago

Great puzzle. Do you ship internationally?

yapyap

8 hours ago

not OP but yes

xyzzy_plugh

9 days ago

Doesn't seem like it. Using the interactive board on the website I was able to produce a solution that only revealed numbers.

nonethewiser

5 hours ago

Seems pretty hard! Even the easy example.

Y_Y

8 hours ago

Those particular rhombuses are typically known as "squares"

dfee

5 hours ago

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)!

ky_vulnerable

7 hours ago

That's really creative. Did the creator come up with the design himself?