Rubik's Cube World Championships

cadaeibfed writes "Coinciding with the 25th anniversary of the iconic puzzle's introduction to the world was the second Rubik's world championship, held in Orlando, FL this weekend. Competing under official World Cube Association rules, competitors from around the world vied for recognition in this nerd olympiad. Some new world records set include the 4x4 solve, solving using only feet, and blindfolded solving. The winner, Jean Pons of France, finished with an average solution time of 15.10 seconds on a standard 3x3 cube. Here are the full results."

Comments

Re:What's that for a standard ?

[metricmusic]

The traditional Rubik's cube has three dice-shaped blocks on each side and was first licensed and sold in Japan in 1980.

Cube Theory = Group Theory

[ankarbass]

While just solving the cube quickly may be interesting. I think it's far more interesting that the cube movements can be thought of elements of a subgroup of a very large permutation group, S48 to be precise. If you have some math background and like abstract things you might want to take a look at Adventures in Group Theory : Rubik's Cube, Merlin's Machine, and Other Mathematical Toys which, despite the title is a fairly serious little math book.

Friend of mine can do this

[raoul666]

Young guy, mid teens. I first saw him do it at a poker tournament I was running. We were using the cube as the dealer button, so whenever it go to him, he'd start working on it. By the time the next hand had started, even if we hadn't even seen the flop, it'd be solved and back on the table. He was probably doing it in 35-45 seconds, but still, it was amazing to watch.

Here's something on the origins of the thing, and

[putko]

http://inventors.about.com/library/weekly/aa040497 .htm

The history of it is interesting. It seems multiple folks developed similar items around the same time.

Fun with Rubik's Cube geeks...

[Geeky]

1. Take cube apart.

2. Put back together in random order so it can't be solved.

3. Give to cube geek.

4. Watch them sweat as their moves don't work.

5. .. er, profit?

Of course, these serious cubers would probably take one look at the cube and immediately tell you it had been tampered with.

Sad news. I'm old enough to remember these when they first came out. I feel very, very old. Anyone remember Rubik's snake?

Cube can be solved in 29 moves or less

[richieb]

The cube can be solved in 29 or less moves. Here is a reference.

I originally worked out the solution to the cube when the Scientific American article by Douglas Hosfstader appeared. I never got my speed much below one minute. I did manage to win a T-Shirt at a Cube contest though - a contents with several hundreds of participants...

Been There, Done That

[ajs318]

I remember the Rubik's Cube from first time around. I knew a few different "complete solutions" -- depending on the initial state, one might be significantly faster than the others. I rarely needed longer than a minute. My friend and I built a fake "cube solving machine" from an old washing machine box, with a hatch tor loading the "scrambled" cube, a drawer for removing the "solved" cube -- and me inside with a bicycle lamp, and a cassette recorder for sound effects!

Obviously you cannot have just five faces "solved", but it is also not possible to have just four faces "solved". You can render a cube insoluble by reversing one of the two-sided pieces, or rotating one of the three-sided pieces. The easiest way to split a cube apart is to rotate one side by 45 degrees, and push the protruding corner piece until its latch pops out. Reassembly is done by inserting one of the two-sided pieces last. I have also seen evidence of very bad sticker-peeling, where one of the two-sided pieces carried the colours of opposite centres and one of the three-sided pieces carried the same colour on each face!

Rubik's Snake was boring: all you could really make with it was a dog and a football.

Rubik's Magic was a little better, because there were two different puzzles on the go: arranging the eight hinged squares to create a shape {4 x 2 rectangle, 3 x 3 square with corner missing, or various solids} and orientating the components of the shape to produce a picture {three separated rings on the rectangle, or three linked rings on the 3-3-2}.

I remember Rubik's Clock best of all. I was given one of the first ones in the country, which my parents got from a toy shop in Yorkshire. It took me nearly two days to crack it -- and then I could not believe just how daft I had been in not spotting it sooner. The secret is to ghea gur pbeare onpxjneqf, ratntr vgf ohggba naq ghea rirelguvat sbejneqf gbtrgure.

Re:15 seconds

[dim5]

Actually, the Fridrich method (which is what most people with times under 30 seconds use), requires 4 looks, and only the first step requires on-the-spot thinking to plan out:

1. Get the edge pieces of the top layer in place (7-10 moves, different every time)
2. Put the corner pieces of the top layer and edge pieces of the middle layer in place (1 of 22 algorithms, all memorized)
3. Get all of the bottom layer to be one color (1 of 41 memorized algorithms)
4. Get all of the pieces of the bottom layer into the right position (1 of 13 memorized algorithms)

The real speed is in planning out the 7-10 moves for the first step in your head before starting (you get 15 seconds to do this), and starting the next step's algorithm as soon as possible once you finish each step. You don't have to plan out the whole solve from the start.

I created an additional step to get the edge pieces showing a cross on the bottom layer before getting the colors on the corners oriented, reducing the number of algorithms to memorize for step 3 from 41 to 6, but it hurts my time (my current best is 54 seconds).

Now, to solve blindfolded, on the other hand, you do need to memorize the cube first. But this could take 90 minutes to commit to memory and plan out, vs. the 15 seconds to only plan the first move. It's really an entirely different approach. I've heard that it's easier to memorize faces as numbers (1-6) instead of colors, but either way I find the whole thing baffling.

Original

[anonymo]

Not really: Japanese, French and American stated that they have the Cube, but only Rubik's was a working toy. E.g.: the Japanese had no documentation about how the invention came, the French had a drawing with stings attaches cubes and the American just did not work and never made into a working unit.
So even if they were not cheating (that is mostly possible because the Magic Cube was produced before patenting and the American and the Japanese patents are newer the the Hungarian) they could not create a working unit and support it with a documented development process.

Rubik's greatest invention on the Cube was that inside the Cube there's a sphere so the construction can turn around on the 3 axes easily.
He had - and only Rubik had - documented, working predecessors like the rubber string solution that didn't last long.

There were some fun incidents on the road, eg. when the Hungarian manufacturer could not produce enough units they bought a lot from Taiwan or Hong-Kong but they were bad quality even if there was a "Made in Hungary" on them :-)

I remember very well because I could not manage to buy one but the radio, TV and newspapers were soon full of it :-) When I got one, people on the bus/metro asked me to borrow or buy for 10x the shop price when I was trying to solve it by myself :-)
At work my boss stopped supervising us when I lent it to him :-)
I still remember the ache in my arms and fingers...

I know a Mathematician who got an early example and she was the very 1st person who looked at the cube on 3 sides, turned the cube to verify that she thought it's positions then hided the cube behind her back and could complete it without seenig it until finished. I was very impressed :)
She showed me that solving the cube is not reversing it to the original positions, "only" making the squares on all sides of the same colour.
You can verify it if you write a letter or number on every square of the same colour in the same position, scramble it and solve the puzzle. you will see that the numbers/letters are in wrong position.
Btw. she wrote the 1st program in Fortran that solved the puzzle just a few months later.