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.
teraflop 12 hours ago [-]
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 8 hours ago [-]
Can you arrange them to make dates that don't exist, or is it designed so you can't?
malnourish 5 hours ago [-]
I love this. Do you ship to the US?
xyzzy_plugh 13 hours ago [-]
This is quite clever.
MontyCarloHall 15 hours ago [-]
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].
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.
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 17 hours ago [-]
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.
I have a smaller version of this puzzle. It's fun and easy to get lost in. My wife was convinced we were missing a piece until I solved it.
smokel 19 hours ago [-]
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 14 hours ago [-]
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.
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 12 hours ago [-]
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.
tromp 14 hours ago [-]
Reminds me of the 1 million pound first solution prize
Eternity puzzle ...
Love Nervous System design. I have quite a few pieces from them including one of their infinity puzzles. Very high quality work.
cadamsdotcom 17 hours ago [-]
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.
colordrops 19 hours ago [-]
Looks amazing but getting 500 errors from the payment flow and the FLUMMOX discount code doesn't work as advertised.
nervous_jessica 14 hours ago [-]
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 14 hours ago [-]
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 14 hours ago [-]
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 11 hours ago [-]
I paused at the statement "Add $55 for free domestic shipping" on the order form.
jeffrallen 20 hours ago [-]
Oh my god, take my money, please. These types of tactile puzzles are the ideal nerdsnipe for me.
Rendered at 04:36:24 GMT+0000 (Coordinated Universal Time) with Vercel.
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
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
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
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).
https://en.wikipedia.org/wiki/Eternity_puzzle
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.