Not quite Mathematic!

April 20, 2024 12:50 PM

Over on gRubiks.com, they've come up with an interesting puzzle solving guide:

If you have an old scrambled [Rubik's] cube just lying around the house, if you’re trying to learn how to solve it on your own and just need a “reset”, if you're looking for algorithms for patterns, or even if you just want to impress your friends—this solver is perfect for you.

Just take your scrambled Rubik's Cube, place it in front of you, and color the squares on the screen as you see them on your cube. Then press "solve", and it will walk you through the solution.
posted by not_on_display (26 comments total)

flathead screwdriver also works
posted by torokunai at 1:10 PM on April 20 [9 favorites]

I found that the one you link to in the main post doesn't work consistantly. It would error out if there were too many moves to solve or something. The one at https://cube-solver.com/ has been working better for me.

I remember the first wave of cube mania, you could go into Mervyn's department store and there'd be a whole display of cubes as well as these thick flyswatter cube smashers for sale. That was so long ago...
posted by Catblack at 1:27 PM on April 20 [2 favorites]

I got a Rubik’s cube when I was maybe in 3rd grade? Didn’t really figure it out at that age, even with a book that described how to solve it with algorithmic sequences. But later, some time in my teens, I decided I was going to try to figure it out.

I no longer had the book, but working just from the idea of the algorithms it described, I was able to develop some sequences and solve it. I am sure that having learned computer programming in the intervening time was quite helpful there.
posted by notoriety public at 1:28 PM on April 20 [2 favorites]

When I get a task like that, I delegate it.
posted by pracowity at 1:46 PM on April 20 [5 favorites]

I no longer had the book, but working just from the idea of the algorithms it described, I was able to develop some sequences and solve it. I am sure that having learned computer programming in the intervening time was quite helpful there.

Related, after the basic algorithms class in undergrad it was amusing to see a lot of that stuff in circulation as regular puzzles. Most notable for me was the Star Wars Knights of the Old Republic using the Tower of Hanoi in game.
posted by howbigisthistextfield at 1:46 PM on April 20 [1 favorite]

So about a decade ago I got a Rubik's cube as a quasi gag gift, like "hey so 80s amirite," and I fiddled around with it for awhile. Of course I had one as a kid in the 80s but could barely manage one side. And with this new one it was much the same story.

One day it hit me: hey, I'm a grown-ass adult. If I can't actually solve this now, when will I? Plenty of people have learned how to solve a Rubik's cube, so why not me? So I went to the main site and right there at the front page is the solution guide PDF. I downloaded it and started working on the cube.

I can only speak of the "official" way to solve the cube; there are a lot of other, different strategies of which I know nothing. The middle squares are set and never move. Solving the cube is at its essence a series of algorithms. If the cube looks like this, do that, with "that" being a series of movements: move the bottom or top left or right, the sides forward or back, the front or back left or right. So if you remember from Playstation cheat codes (left, right, circle, triangle, down, etc), it's much the same thing: algorithms. In three dimensions.

Completing it the first time took hours and hours, I'm sure. Then you do it again and your muscle memory kicks in bit by bit and it gets easier and faster. Then I could abandon the guide and just go by some notes on certain algorithms. Then, finally, after countless tries, I could solve it without notes.

I still have that Rubik's cube, battered and grody, and I pick it up to solve it a few times a week. Takes me about a minute and a half; I have NO IDEA how those speed cubers solve it in mere seconds. I hope it's just a little bit of brain exercise that keeps the brain alert, knock on wood.
posted by zardoz at 2:05 PM on April 20 [9 favorites]

This is a good idea, one of those things that should of course exist in the world and I’m glad it does
posted by Going To Maine at 2:18 PM on April 20 [1 favorite]

I still have that Rubik's cube, battered and grody

Yes, but is it properly grody? Is it grody to the max?
posted by notoriety public at 2:20 PM on April 20 [15 favorites]

As time approaches infinity grodiness is maximized.
posted by JHarris at 3:35 PM on April 20 [3 favorites]

Gag me with a spoon (which also works to jimmy out the individual pieces) BUT THATS NOT THE POINT
posted by not_on_display at 3:50 PM on April 20 [3 favorites]

Or you could use magic.
posted by Faint of Butt at 4:14 PM on April 20 [1 favorite]

Seconding zardoz's experience -- I learned the solve over a weekend, a month or two ago. It was much easier than I expected. There are only four algorithms you need to memorize, and two of them are just extensions/variations of the first one, so really only two. That and remembering which algo to use for which step of the process is all there is.

Takes me about a minute and a half; I have NO IDEA how those speed cubers solve it in mere seconds.

Basically, they memorize a lot more algorithms. A lot more. The algos you learn for a basic solve are ones you can just repeat for each step until that step is eventually finished, and it takes more or fewer repetitions based on the scramble. Speed-solvers learn specific algos for every specific case.
posted by rifflesby at 4:28 PM on April 20 [2 favorites]

One day it hit me: hey, I'm a grown-ass adult.

So I picked the SOB up and threw it in the garbage. I've got lots of other stuff I'd rather do.
Problem solved.
posted by BlueHorse at 5:09 PM on April 20 [5 favorites]

wait i became a grown-ass adult so i could just do this shit all day and not be told to go do something constructive
posted by not_on_display at 6:25 PM on April 20 [3 favorites]

I could not do one of these things even if they were all white, or blue, whatever. I've never owned one and that's good because it seems I get this crazed look in my eyes when I beat useless garbage to bits with my six pound sledge hammer which sortof makes people edge away nervously.
posted by dancestoblue at 7:45 PM on April 20 [1 favorite]

I had a look at the solution PDF that zardoz mentioned and it looks very good. It's a lot of pages, but not dense, and the first part is just describing the basics of the cube and notation. The illustrations area really good too.

A few years ago I learned from J-Perm's youtube video which worked for me, but I'm not sure I'd recommend it. The very last step involves a long sequence that works fine if you do it right, but if you mess up you have to start the solve over from the very beginning which I found very frustrating as a beginner. I eventually learned the Roux method from Kian Mansour's tutorial. I think Roux is underappreciated as a beginner method because of how it largely avoids breaking earlier progress. The last part is especially forgiving, because it only requires turning two layers (M and U) and as a result cannot wreck the first two blocks or the corners.
posted by swr at 1:05 AM on April 21 [1 favorite]

A few years ago I learned from J-Perm's youtube video which worked for me, but I'm not sure I'd recommend it. The very last step involves a long sequence that works fine if you do it right, but if you mess up you have to start the solve over from the very beginning which I found very frustrating as a beginner.

Screwing up and starting over again is part of it. Happens to me all the time. I can solve a cube and have done so for years, but just today after posting above I picked up my cube and solved it--but screwed up halfway through. Started again. I sometimes screw up on the very final stage and somehow really mix things up and have to start again. The more you are forced to do it, though, the more practice you get, and the less you screw up...in theory, anyway.
posted by zardoz at 2:29 AM on April 21 [1 favorite]

One of the worst tricks you can play on someone is to screwdriver apart a cube, and then put it back together but with one piece in the incorrect orientation for its place. Then scramble it, and wait for some unsuspecting victim to attempt to solve it.
posted by notoriety public at 8:42 AM on April 21 [2 favorites]

So part of the reason modern speedcubers are so fast is indeed that they have spent a lot of time learning a lot more algorithms than you'd think is sensible to learn, but a big part is also that a modern cube is a very different device than the clunky spring-loaded device Ernő Rubik put together back in 1974. Last year when some new speedcubing record was set I ended up buying the cube it was set with and it's amazing to see next to my modern Official Rubik's Cube.

The Rubik fundamentally doesn't want to turn; it's held together by a lot of friction and tension. It's easy to get it misaligned, and you have to manually square it back up before you can turn it. You pretty much have to use both hands to turn it.

The X-Man wants to turn. It's got very little friction between its individual cubelets. And yet it also wants to be aligned, because there's little magnets inside of every cubelet to help that. The internal corners are rounded, too; get this thing a little misaligned and it is eager to slide back into alignment. There's holes on the internal faces of every cubelet where you can use a jeweler's screwdriver, or the little plastic tool that came with the cube, to adjust the placement of the magnet. You can lightly pinch it between your thumb and one other finger, and use another finger on the same hand to flick it through a quarter-turn or a half-turn in a fraction of the time it takes to turn the Rubik's. You can do this with your little finger, which is the weakest one.

Here's a photo of the X-Man and a Rubik's. I had them both squared off with the top two layers solved, and gave the middle layer a light flick with my middle finger; notice how much further the X-Man went than the Rubik's. They are very different devices. It's like comparing minivan to a Fomula 1 racecar.

All that said I used to know the "Simple Solution To Rubik's Cube" method when I was a kid in the eighties and now all I can do is half-assedly get the top two layers together. I haven't spent time sitting with this super-fast new cube and getting to the point where I can just sort of pick it up one-handed and have it solved a couple minutes later, never mind stuffing a couple hundred turn sequences into my head for doing it minimal steps in a half a minute.
posted by egypturnash at 9:27 AM on April 21 [6 favorites]

The Speed Cubers on Netflix is a fascinating documentary about two top ... speed cubers. Even my wife liked it.
posted by neuron at 10:24 AM on April 21 [1 favorite]

Hm, I wanted to see how the solving site works but I don’t have a cube to get a valid scrambled state from. If you make one up you get a “your cube is not colored correctly” message, which, fair. However if you input the pattern from the cover of the solving guide linked by swr above (cover illustration shows a scrambled cube and a solved cube) you also get that error message.
posted by yarrow at 10:26 AM on April 21

yarrow, the image in that PDF only shows three sides, which is not enough to uniquely identify the cube state. In the grubik's solver you have to turn the cube around to fill in the other faces. Click and drag or use the buttons to rotate.

If you want a valid scramble to try without having a physical cube, you can use cstimer to generate a scramble, and click the tools button to see the cube faces. You can also plug the generated scramble into alg.cubing.net to see a 3D cube, or just enter your own moves there to scramble it.
posted by swr at 11:01 AM on April 21 [2 favorites]

flathead screwdriver also works
Not sure if you're referring to-
1)using it as a weapon of destruction
2)Using it to pry out a side piece in the cheaper cubes (but you can do that with your thumb, you don't need a tool), or
3)using it to unscrew the center pieces on the better cubes, which is the proper method of getting inside (but all the ones I've seen use Phillips screws)

Team Roux here. I was inspired by a post on the blue years ago to try to get my time down under 3 minutes. Roux got me down to around 45 seconds. Nothing competitive, but good enough to impress the mortals. It's also a great finger exerciser, my kind of Fidgit.

I got my first cube back in the 70's. Most cubes then had white across from blue, and yellow across from green. (That wouldn't fly in the FPP solver.) I would imagine that would really mess someone up who was using Roux or CFOP, but it wouldn't bother the first system I learned, or the solving method in the FPP.
posted by MtDewd at 2:46 PM on April 21 [2 favorites]

Thanks swr! For some reason I jumped to the assumption that three faces was enough for a unique cube.
posted by yarrow at 4:54 PM on April 21

An engineer and a mathematician are sharing a hotel room when a fire starts in their trash can. The mathematician wakes up, looks at the fire, looks at the bathroom with a nice big bathtub, declares "there exists a solution" and goes back to sleep. The engineer actually throws the trashcan into the tub and turns the water on. (there's a statistician variant where the statistician wakes up, sees the fire in the trash can and sets the drapes and the desk on fire to get a sufficient sample size to know what to do, but that's not 100% relevant here.)

We had a bunch of cubes and other twisty puzzles around, but I'd look at them and declare "there exists a solution" and not commit any algorithms to muscle memory and implement the solution. But then in the early months of Covid-19 lockdown, one of my kids was 10/11/12years old ish, at that point where brainpower is increasing. So we watched this Wired video a couple times, and by the summer everybody in the house could solve the 3x3 without a cheat sheet on algorithms. Some of the moves are satisfying in a "checkmate in 2 moves" kind of way: get this out of the way of that, then when you put this back in place, that comes with it for free!

N'thing everybody who doesn't know how you get to the 4-second-solves, though.

Also, learning how to solve it has made me very picky about comics that show cubes: This one shows an edge piece with white on one side, and yellow on the other. But on ye olde standarde cube yellow and white are opposite sides! I bet they felt pretty foolish lol.
posted by adekllny at 7:09 PM on April 21 [1 favorite]

White and Yellow-
Here's a picture of the front cover of a book, possibly the one I learned from first.
You see the White and Yellow because white is across from blue, and yellow is across from green.
The solving system there is to start with a blue cross and the top, last layer is white.
posted by MtDewd at 3:46 PM on April 24