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Lars Petrus

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Rubik’s Cube

Having a wide variety of more or less obscure hobbies seems to be an integral part of who I am. Some of these hobbies only remain in vogue for a short period of time and are then left fallow, perhaps indefinitely. I thought that Rubik’s cube (henceforth cubing or speedcubing) might be such a transient pastime. I was wrong. It has come back more than once, and since I want to keep track of what I’m doing and also post some updates, I thought that creating a page for the cube would be a good idea, so here it is. The structure is based on the various kinds of puzzles related to Rubik’s cube, with a list of all related posts at the very bottom.

This post was last updated 2012-03-30.

Why Rubik’s cube?
Rubik’s 3×3
Rubik’s 3×3 blindfolded
Rubik’s 3×3 multiple blindfolded
Fewest moves
Rubik’s 4×4
List of related posts
Interesting or useful links

Why Rubik’s Cube?

The most common question I hear when cubing is: Have you solved it? The correct answer is, yes, tens of thousands of times (including blindfolded, backwards, one-handed and in my sleep), but I never say that. Most people don’t realise that the challenge is not gone just because the cube has been solved once. It can be solved in many ways (such as few moves, quickly or blindfolded), all which require a different way of thinking and a different kind of understanding of the puzzle. To be frank, I’m not extremely talented at this (no, I’m not being modest here), but I can understand the methods others have developed and learn. Striving for ever more elegant or quicker solves is like any sport (compare attaining high scores in a computer game or perfecting a golf swing). Trying bigger and/or harder puzzles (such as the 4×4 or Megaminx) is of course also a challenge I enjoy overcoming.

In addition to this, cubing fills a completely different function: it occupies my hands while my brain is doing something else. This phenomenon should be familiar to anyone who likes knitting or spinning pens using their fingers. Some algorithms and moves are so well-rooted that I need no conscious effort to execute them, which means that I can listen to a lecture with full concentration and solve the cube simultaneously, although not at top speed, perhaps. Sitting on the bus, I find it boring to only listen to audio books, but if I cube at the same time, it’s suddenly a lot more interesting. Thus, most of the time, the cube itself is only a sideshow. Cubing is a kind of meditation and/or therapy.

3×3 Rubik’s

This is the original cube and the puzzle I’ve spent by far the most time on, although I only started “seriously” during the summer of 2009. I use Lars Petrus’ method, but use Friedrich for the last layer. Since 2009, the cube has been lying untouched for months at a time, so this is not something I take very seriously, although I occasionally cube quite a lot. I have written about the 3×3 before, please refer to the following posts: Speed cubing, My first solve (Swedish), Christmas puzzles. Related posts: See below.

Best time: 0:16.75
Best average of 5: 0:21.27
Best average of 12: 0:22.20
Best mean of 100: 0:23.82

3×3 Rubik’s one handed

Of course, the 3×3 can also be solved one handed, something I started in early 2012 when I felt I didn’t really get anywhere with normal 3×3 solving and wanted to try something new.

Best time: 0:32.33
Best average of 5: 0:39.48
Best average of 12: 0:44.80
Best mean of 100: 0:53.29

3×3 Rubik’s blindfolded

As soon as I started achieving times below one minute for the 3×3, I started looking at blindfolded cubing. I’m using a 3-cycle orientation permutation method (3OP). Blindfolded cubing is a two stage problem: the cuber first has to memorise the state of the cube and then, while not looking, solve it. Although this is a lot harder than ordinary cubing, it’s not superhuman in the way it might look to an outsider. I’ve written about blindfolded cubing in more detail here: Solving Rubik’s Cube blindfolded. Related tags: Blindfolded cubing.

Best time: 5:51:13
Best average of 5: 8:13:68
Best average of 12: DNF

3×3 multiple blindfolded

Same as above, but instead of trying to solve one cube quickly and accurately at a time, you look at several cubes at once, memorise them and then solve them in sequence without looking. The method is the same as for one cube, but obviously requires a lot more memorisation and clever memory tricks. I haven’t done this very much and so my memorisation is very, very slow.

Best result: 2/3 in 47:58:93

Fewest moves

Fewest moves is what it sounds like. You receive a scramble (a string of moves to scramble the cube) and the you have one hour to find the solution to that scramble that requires the fewest moves. This is really interesting and there are lots of creative and fun stuff you can do, the only problem is that it takes quite a long time and that luck actually matters quite a lot. I don’t do fewest moves very often, but I still think it’s cool.

Fewest moves: 36

4×4 Rubik’s

I bought my first 4×4 in the autumn of 2009. I haven’t spent that much time with this one, but I think its quite interesting. It combines all the tricks of the 3×3 solve with some new ones (I use centres first, two edge-pair swap and then Petrus’). In a way, this puzzle is more interesting than the 3×3, because it adds two fairly creative steps to the process (though I suppose bigger cubes do this to an even higher extent). I haven’t written anything detailed about the 4×4, but I did write briefly about it here: Christmas puzzles. Related tags: See below.

Best time: 2:05:80
Best average of 5: 2:26:99
Best average of 12: 2:42:92
Best mean of 100: N/A


I first solved the Megaminx on Christmas Day, 2009, after borrowing it from a friend. I’m not sure what I think of the puzzle in terms of speedcubing (speeddodecahedroning is not a very pleasant word neither to write nor to say), I might need an new megaminx. As it is now, I can finish it in about ten minutes, but most of that time consists of looking for pieces and trying to remember which side is supposed to be up. My current colour scheme must have been designed by an idiot, because even I (with normal colour vision) think it’s really hard to tell some of the colours apart quickly. I wrote about the Megaminx and my first solve in this post: Christmas puzzles. Related tags: Megaminx.


Useful or interesting links

Speedcubing on Wikipedia
The Petrus method
CFOP tutorial Erik Akkersdijk
Bob Burton’s CubeWhiz.com (my favourite)
3OP blindfold method by Shotaro Makisumi
Speedsolving.com (forum)
World Cube Association (competitions, official site)

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Speed cubing

“Do those things still exist?”
“I also had one when I was young!”
“How do you do that?”

These are the three most common things I hear when speed cubing (perhaps it should be quotation marks around “speed”), which simply means trying to solve Rubik’s Cube (Wikipedia) as quickly as possible (see also this antique post in Swedish I wrote the first time I solved the cube, which is almost five years ago now). This is a hobby of mine which has come and gone a number of times, usually with fairly long intervals. This time around, though, is probably the longest, which is why I now choose to expound on the topic a little bit. I also decided to write this post now because yesterday I finished the cube faster than one minute for the first time (58 seconds) and this is the goal I specified on my 101-in-1001 list. In this post I’ll try to answer two questions: how and why, which should be the most common ones.

First of all, solving Rubik’s Cube the first time is pretty hard. If you don’t have access to any help whatsoever, it would be almost impossible for normal people, or require an extraordinary amount of time (far more than I would be willing to invest). Even using help, it’s not easy, even if there are superb guides out there. Of course, solving the cube the first time is radically different from trying to solve it as quickly as possible. The first time, it’s a struggle to understand the cube, but after that, it’s a creative quest for more and more optimised movements and sequences (not only ways of actually moving layers of the cube, but also physical ones, i.e. how to rotate the layers with your hands). Here’s how it should be done (standing world record, set in 2008 by Erik Akkersdijk):

Solving Rubik’s Cube for speed isn’t even potentially boring at my level, but might be if you’re going for the world record, because it would involve memorising a vast number of perfect sequences leading up to a solved cube from various positions. I use Lars Petrus‘ model (already linked to above), because it’s possible to complete only memorising two sequences of around 15 rotations in all. I think it is one of the better methods for beginners as well, because it fosters understanding of the cube and Lars doesn’t freely give away advice he feels the beginner should find out on his or her own.

Then the big question: Why? Challenge, therapy and something to occupy my hands with, in roughly that order. Let me explain. Solving the cube for speed is a challenge in many ways. It’s intellectually stimulating and requires a number of very different skills. Not only do you have to be able to understand how the cube works, but you have to work out the fastest way of doing something. Constantly, you must scrutinise your method to find better alternatives. Also, Rubik’s Cube is therapeutic in the same way I can imagine knitting to be. It puts the mind at rest and if really focusing on new ways of doing something, it’s difficult to think of something else. However, the opposite is true when relying on experience. I can easily solve the cube and have a normal conversation at the same time (more often, I combine cubing with listening to audio books on trains, flights and so forth). It keeps my hands occupied and my mind can roam freely.

In short, Rubik’s Cube today is an underrated, challenging and cheap form of entertainment. I don’t know how long my current cubing period might last, but even if I’ve accomplished my original goal of one minute, I don’t feel satisfied and when I put it down, the cube will probably keep resurfacing now and then as a somewhat eccentric pastime.

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Online Highlights 2

I haven’t spent much time browsing the Internet lately, mostly because I’ve been too busy with applications for next year, as well as normal studying. However, I have come across a few websites I feel are worth sharing (see other Online Highlights). Below, I’ve tried to explain why.

5 Real Life Soldiers Who Make Rambo Look Like a Pussy –  I think the title is sefl-explanatory, this is an article about five soldiers with exceptional performance records, some of them so outstanding that Hollywood decided to reduce them because the audience would think it uneralistic if the true story was told. This is a good read.

Open Yale Courses, Game Theory –  This is also what it sounds like. Yale University has started a series of free courses that can be downloaded from the web. I haven’t finished this one about game theory yet, but it’s very good so far and I can recommend it if you’re interested. Even though it’s possible to listen to most of it, I suggest downloading video.

Internet Archive: Wayback Machine – I learnt about this project in the most recent edition of the Economist. Basically, it’s an archive for the web, storing old versions of website. For instance, you can have a look at what your own website looked like five years ago. This might also be useful for retrieving lost data.

Lars Petrus on Rubik’s Cube – My interest for Rubik’s Cube has ben revived lately and this is the best site I’ve found so far. His method is intuitive and pretty good, and it does not require you to memorise a whole lot of sequences. Admittedly, Petrus’ method has declined in popularity among the world’s fastest speedcubers, but it’s still perfect for beginners and intermediates.

Chinese Language and Culture for International Students – I provide this link not so much because I think somebody else will apply, but rather because somebody might be interested in what I’m doing. Right now, that’s trying to apply for this program at National Taiwan Normal University in Taipei, a four year Bachelor’s Degree program. Nothing is decided yet, though, because I need to aquire a scholarship as well. I will post something specifically about this as soon as I have more information.

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