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Let's ramble about twisty puzzles

By Misery · Nov 11, 2019 ·
  1. Okay. Time to talk a bit about hobby #2.

    This time, we enter the wild world of twisty puzzles. There's some crazy stuff in here, but let's start with the one that everyone knows, and in the process, I'll talk a bit about how I got into this.

    Pic1013.jpg

    The original Rubik's Cube. Everyone knows what this thing is, and everyone knows just how it works. Scramble it up by twisting the different faces of the cube, and then attempt to get it back to it's starting state. Everyone knows that. And everyone knows that the bloody thing is nigh-impossible for anyone to solve. Twist any side once, and you're moving 8 pieces at the same time (center piece doesnt count). How can you get individual cubes into position when every slight movement dislodges so many? That's what I thought too.

    I randomly stumbled on some Youtube videos of someone solving this, and talking about the way they were doing it. And I saw some other puzzles too. I have no idea why Youtube decided to throw that in my face that day, but it got me intrigued. I looked around, and found more and more videos about these things. Lots of people solving them. And I figured... wouldnt it be neat to accomplish that? There's all sorts of instructional videos on here... maybe I could do it too. So I went and picked one up, and looked at the official tutorial video from the Rubik's company. The "introductory" method for solving it.

    Yeah, that method works, but... hoboy. It turned out that memorization was the key to their method. LOTS of memorization. Yeah, that sounds strange... how could memory have anything to do with something that becomes so random? But the way these methods work is that the person will look at certain parts of the cube, and spot things there. For instance, looking at the yellow side, they'll look specifically for where any yellow pieces on that side are. This part is typically done after some other parts are already done... it's not the first step. But they'll see the exact arrangement, and then purely from memory, execute an algorithm... or long series of moves... that pertains to that exact arrangement of yellow stickers. A single algorithm could be anywhere from 8 to 20 moves. But more ridiculous is just how many need to be memorized. The most popular method uses a ridiculous 75 algorithms or so (and that's how those speed-solvers do it, too). Absurd! I can barely remember the address of my house... how could I remember THAT? A bit disappointed, but I looked at more stuff anyway.

    But then I found something else. The so-called "ultimate method". 75 algorithms? No. There are 2. Two of them. Just two. One is 4 moves long, and the other is 8. Also gone is the need to spot specific configurations of anything.

    fig2a.jpg

    See those 3 marked pieces? The first of the two moves, called the "edge piece series", takes those 3 pieces and swaps them. Oh, it'll do things to the surrounding corners and such, but that's irrelevant. The point is that it swaps the EDGES, 3 of them, without affecting other edge pieces. Exactly how you do it depends on how you want the three to swap. The first step of the solve, then, is to put all the edges into place. It's a little more complicated than that... the yellow side is the final side I do, and there's extra complications to that, but I'll get to that in a minute. So at this point, the edges are all done. Only the corners remain. But wait, how could you move JUST the corners without screwing up all the edges?

    fig3c.jpg

    The "corner piece series". Like the edge thing, it takes 3 corners and.... well, "swaps" them isnt quite the right word. It moreso "rolls" each one alongside the face you are manipulating. It's a bit hard to explain, but the exact effect of this is perfectly predictable. This is the one that is 8 moves long, and it's actually a simple sequence that's easy to remember. It never moves any of the edges. Just the corners. It makes sense if you do it slowly and watch it, you can see how it functions, but I wont explain that here.

    So, using that, you roll corners around until you've got most of them done. As a rule, you will have exactly three corners remaining that need to be placed. However, most of the time, these will be on different sides of the cube. How the hell are you supposed to deal with that?

    This is where we come to the 2nd reason why I use this method. See, I dont like the idea of using pure memory to do these. That's not really "solving" a puzzle to me. That's just repeating a solution someone else came up with. This method, it doesnt do that. It gives you the two algorithms, and a sort of vague idea of how to use them. But actually doing it is going to take actual logic and spatial reasoning. Sure, you can swap 3 pieces... but WHICH 3 pieces do you swap, and when, and why? It's gonna be different each time.

    Particularly in the final step. Those 3 pieces that are all over the place, well... the trick is to move them so they're all on the same side in such a way as to where using the corner series will put them where they need to go. This means twisting the whole thing. It needs to be very specific to work, because the corner series is very specific in exactly HOW it rolls them. So, get the three pieces onto a single side, in the right way (doing it in just any way wont do!). Even if it completely screws up the rest of the cube. Which it will. But here's the thing: You manipulate the cube to put them in place, perform the series, and then sort of un-manipulate it. You do the exact opposite of the moves you used to position those, and it restores the cube.

    What makes this so interesting is that there's this big puzzle of trying to figure out what sequence of moves you need to do in order to get those pieces ready for the corner series. There's no algorithms here. It's pure logic and spatial reasoning. You have to figure out this series of moves... which can sometimes be quite long... yourself. The way I do it, I write down each move I make (using basic notation) as I make them, once I've figured it out. When it's time to reverse, well... just follow what I wrote, but backwards.

    And BAM. It's done. Cube solved.

    Now, this might all sound kinda hard to follow. And indeed, I struggled with understanding this at first. Because again, pure memorization isnt enough. You have to actually understand what's going on, and the many ways that those 2 movesets can be used. Because indeed, there are ALOT of ways to apply them. This is also why this method cannot be used for speed-solving.

    Once I understood it, it went from "bloody impossible" to "too easy now". There was no challenge left in the basic cube. And from there... it was time to really dive in. This had been the easy part. Now it was time for the ACTUAL challenge.

    (continued in part 2)

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