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Lego Robot Solves Any Rubik's Cube In 12 Seconds224

Posted by timothy
from the yes-yes-it's-not-the-world-record dept.
kkleiner writes "Cube Stormer is the latest creation from Mike Dobson, aka Robotics Solutions, and not only is it made entirely out of Legos, it can solve any 3x3 Rubik's cube in less than twelve seconds. Often it can finish in less than five! This thing looks bad-ass and is incredible to watch."
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Lego Robot Solves Any Rubik's Cube In 12 Seconds

• Stickers (Score:5, Funny)

by Anonymous Coward on Thursday February 18, 2010 @04:44PM (#31191606)

And heres me expecting to see a robot that can quickly rearrange the stickers.

• Re:Stickers (Score:4, Informative)

on Thursday February 18, 2010 @05:16PM (#31192090) Homepage Journal

And here's me expecting not to see stories from 9 years ago repeated.

http://slashdot.org/article.pl?sid=01/09/07/0133248 [slashdot.org]

• Re: (Score:3, Funny)

As I scroll through looking for "Funny", I see jokes from 9 years ago repeated.
• Re: (Score:2)

You do realise it was just spray painting it on the far side hidden from camera view!
• Re: (Score:3, Funny)

When I was a small child of 4 or 5 in the early 80's, my Dad got a Rubik's Cube for Christmas. He found it amusing. A few days later I brought it to him, completely solved. He was amazed! Not only had his genius son shown remarkable problem solving skills at such a young age, I had even managed to put a few of the stickers back on straight.
• Re: (Score:3, Interesting)

When I got stuck on the Rubiks cube, I worked out how to disassemble and reassemble the whole cube in the correct order. Peeling off the stickers never even occured to me.
• Cool (Score:4, Funny)

on Thursday February 18, 2010 @04:44PM (#31191608) Homepage

Cool, just make sure it doesn't mistake your head for a Rubik's Cube. :)

• This Video is FAKE (Score:4, Informative)

on Thursday February 18, 2010 @06:45PM (#31193182)

Okay, it's not FAKE but it's completely and entirely dishonest. I can solve the rubik's cube in about 20 seconds over an average of 12 solves, so I have a thorough understanding of human speed-solving. Computers, on the other hand, would go for some idea solution that a human brain is not capable of producing. This is especially true since the robot in this video moves EXTREMELY slowly, about 1-2 turns per second on average. Human hands can EASILY sustain 3-5 moves per second. This computer, to solve the Rubik's cube in 2 seconds as in the first part of the video, or 4 seconds as in the second part of the video, would have to be able to solve the cube in 4-10 moves. The optimal solution for solving a rubik's cube has already been bounded at about 18 moves (look it up).

Still don't believe me? Start watching and replay the video from 30s onwards. Freeze the video when the timer starts at 0:00 and look at the cube, it is actually a single 90 degree rotation away from a fully solved state.

The 4s video beginning at 1:07 shows several rotations of the WHOLE CUBE without making any actual moves, then does 4 turns and solve it, which means that it wasn't anywhere near a scrambled state to begin with.

More evidence that it's fake? Is there any information on this other than a 2 minute video on youtube?

• Re: (Score:3, Informative)

The optimal solution for solving a rubik's cube has already been bounded at about 18 moves (look it up).

Only in the worst possible configuration of the cube. 18 moves can't be the lower bound for every cube, because there exist many configurations that can be solved in less than 18. (Like the one you mentioned at 30s) If you'd read the rest of the wiki article you probably just consulted you would have seen that there even configurations that need over 20 moves too.

As for turning the cube then solving it in 4 moves, look at the computer and note a single view of the cube. The machine has to determine the star

• Re: (Score:3, Informative)

It's dishonest because for both the "2s" and "4s" solve of the cube, the cube was not fully scrambled. In fact, for the 2 second solve, the cube only had one single turn on it when the timer started. It is dishonest because he CLEARLY and obviously did not scramble the cube for both the 2 second and 4 second time. Look at the video at 30s and freeze it at the start of the timer and you'll see exactly what I mean. I can't honestly believe that you don't know what I mean by "dishonest" if you haven't done thi

• Re:This Video is FAKE (Score:5, Informative)

on Thursday February 18, 2010 @10:14PM (#31195174)
If you watch carefully, the "Full Solve", which states such and claims to be a "totally random cube (Honest)", takes 10.75 seconds, including inspection. The 2.01 second solve is a demonstration of the MINIMUM time required for "inspecting and making one twist" on an unsolved cube. It is the blogger, and not the video, who makes the claims of solving in 2.01 seconds, and while it technically is a solve, the inventor rightfully does not claim such. The world record human solve of 7.08 seconds is not including the untimed inspection period. I would not consider this a dishonest video, since the video does not claim anything but the 10.75s solve to be a real solve, which by the rules of the second video's competition, would actually be an 8.74s solve....
• Re: (Score:3, Informative)

It's dishonest because for both the "2s" and "4s" solve of the cube, the cube was not fully scrambled. In fact, for the 2 second solve, the cube only had one single turn on it when the timer started. It is dishonest because he CLEARLY and obviously did not scramble the cube for both the 2 second and 4 second time.

This isn't dishonest. I watched the video and saw that the machine can solve a trivial problem in one move. The video didn't disguise this in the slightest. You can see a more complex configuration being solved elsewhere in the video and this obviously takes more time.

Look at the video at 30s and freeze it at the start of the timer and you'll see exactly what I mean. I can't honestly believe that you don't know what I mean by "dishonest" if you haven't done this simple task for me.

At 0:30 I see a cut from one sequence to another. I didn't think I was watching a real demonstration until I saw a start-to-finish run without any cuts.

And yeah, you were right about the 18 moves thing, I was quickly looking for a number to back up my argument. The fact that 18 is actually lower than the optimal lower bound strengthens my argument instead of weakening it, though.

No, it doesn't. Your original argument seemed to be that 18 moves is the lower bound for so

• Re: (Score:2)

Okay well apparently my original comment is too long for people to read through, so:

tl;dr: freeze the video at 30s and look at the cube in its "scrambled state". You'll see that 2/3 of the cube is lined up, and anybody could make that last turn in 1 second to "solve" it.

• Re: (Score:3, Informative)

He isn't claiming that it is fully scrambled in the 2s one - for the one immediately after he specifically says to get ready for a "full solve" and has big letters come up saying the NEXT CUBE is a "totally scrambled cube". The 2s was just a demonstration of the machine moving and is implied as such. You could maybe make a case about the 4 second one, but I'm not sure he's claiming that one to be a full scramble either.
• Re: (Score:2, Funny)

If I were you, I would delete all the "it's dishonest!" comments from youtube and slashdot. I saw the Rubik's Cube Robot and Schwarzenegger heading over to your house...
• The Lego-Coolness equation (Score:4, Funny)

on Thursday February 18, 2010 @09:02PM (#31194514) Journal

Um

Being made of Lego raises the coolness of an object to it's own power. So if a machine solving a Rubik's Cube had a coolness factor of say, 100, then a machine solving a Rubik's Cube MADE OF LEGO would be 100 ^ 100, or:

100,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

I mean I don't even care if it's fake... it's still epickly cool.

• Re: (Score:3, Insightful)

I think your definition of "fake" and mine differ. The video is certainly not fake. It's a Lego machine that can solve a Rubics Cube that is being blogged about by some random overzealous blogger. The 2 and 4 second solves were probably the engineer running test cases where he took a solved cube and rotated it a certain number of times to see if the machine would then solve it in the same number of rotations. It's fairly obvious that the machine isn't capable of solving a random cube in 2-4 seconds beca

• Re:This Video is FAKE (Score:5, Interesting)

on Thursday February 18, 2010 @09:52PM (#31194980)

The next to last solve (at 41s) takes 21 moves*, and is the only cube claimed to be random... thus, I don't see any dishonesty. It takes around 1.9 seconds to analyze, about 0.4 seconds to reset/process, and the remaining 8+ seconds to solve. Therefore, it makes on average between 2 and 3 turns per second.

Humans do not include inspection time in the speed calculation (at least, that's the case in the accompanying video of the world record). An apples-to-apples comparison, therefore, would be the human time at 7 seconds and the robot at a little over 8. I couldn't follow the world-record video, but I think I saw at least one mistake (a move followed by the opposite move) and a little hesitation. So, you're probably correct in the 3-5 moves per second for humans.

*21 includes twice that the computer simultaneously moves two faces, each counted as two separate moves. 180 degree moves are counted once.

• That's fast (Score:3, Interesting)

on Thursday February 18, 2010 @04:45PM (#31191622)
Think 99% of the world population can't do that :P
• Re: (Score:2)

Think 99.9999% of the world population don’t give a flying fuck about it too. :P

• I for one will be slack jawed at the awesomeness (Score:4, Funny)

on Thursday February 18, 2010 @04:46PM (#31191648)
of our new Lego robot masters.
• Re:I for one will be slack jawed at the awesomenes (Score:2)

As will I, when I see one that can build other Lego robot masters.

Pervert.
• Cheating! (Score:5, Funny)

on Thursday February 18, 2010 @04:49PM (#31191690) Journal
That thing got four arms. Come on, that is cheating.
• Re: (Score:2)

Poor little tink-tink.

• I solved a Rubiks cube in 12 seconds once (Score:5, Funny)

on Thursday February 18, 2010 @04:51PM (#31191724) Journal

All I needed was 6 different paint brushes dipped in 6 different colours.

• Re: (Score:2)

All I needed was a flat-head screw driver.

• Re: (Score:2)

I just threw the thing into a can of paint, but I still lost because it took too much time to forcibly submerge the thing...
• Re: (Score:2, Funny)

I just threw mine out the window! There, problem solved!
• Re: (Score:2)

I did it in 2 seconds. Had 6 surfaces with color pre-applied, and just touched each of them with a side of the cube. ;)

• How they are doing it? (Score:5, Interesting)

on Thursday February 18, 2010 @04:53PM (#31191744) Homepage
Unfortunately, the linked to post and video doesn't give much details. Naively, I expect that the computer program is first figuring out very quickly what the series of movements to solve the cube and then implementing those. There are around 4 * 10^19 possible configurations for a Rubik's cube, but the group theory allows one to work out what steps to take without having to do very exhaustive searches since the Rubik's group is very well-behaved. However, this assumes one is in an actually solvable configuration. I'd be curious to find out if they've debugged the device well enough to make sure it doesn't hang or get in some infinite loop if one gives it an unsolvable cube (not all possible permutations of squares are solvable. Most trivially, edges need to stay on edges, corners on corners and centers on centers. But some configurations are still not solvable. For example, if one swaps two center stickers it isn't hard to see that that lays outside the Rubik's group of reachable permutations).
• Re:How they are doing it? (Score:5, Insightful)

on Thursday February 18, 2010 @04:58PM (#31191836) Journal

They probably didn't debug it much, but in actuality - most of it is pattern recognition. If you look straight down the corner of one Rubiks cube, you will see 3 faces of it, and that is all you actually need to solve the Rubiks cube. All the pros merely remember the patterns and the steps required to solve each pattern. Rotate the cube 90 degrees and the pattern still exists, even though things are in a different shape.

Really, the programming side of this isn't that impressive once you know how Rubiks cube solving is done. I'm more impressed at the speed, which I've normally found Lego technic and Mindstorm products to be a little laggy in commands and slow to operate, keep in mind though, that was the stuff I used like 7 years ago.

• Re: (Score:2, Interesting)

It looks pretty simple to me. You put it in and it snaps shots of the 6 sides of the cube. Those are interpreted by the computer which probably uses a standard solving algorithm. The solution is translated into movements for the robot, and off it goes.

My guess would be if it was impossible to solve, it wouldn't start doing anything, the software would complain. No Rubik's cube is impossible to solve without physically messing with the cube (as you pointed out, swapping stickers for example). If you start w

• Re:How they are doing it? (Score:5, Funny)

on Thursday February 18, 2010 @05:10PM (#31192006)

You put it in and it snaps shots of the 6 sides of the cube. Those are interpreted by the computer which probably uses a standard solving algorithm. The solution is translated into movements for the robot, and off it goes.

I'm stunned. And here I was thinking it worked by magic. Is that REALLY how it's done?

Sorry, I'm just feeling rather cynical today. Pffft.

• Re: (Score:2)

I've got one that just does random actions. Statistically, it has to get solved at some point.

• Re: (Score:2)

They probably used Herbert Kociemba's program:
http://kociemba.org/cube.htm [kociemba.org]
check the webcam section.

Kociemba is the creator of a very fast algorithm that solves most of the cubes in less than 25 moves in one second, using a two-phase technique (by using large precomputed tables).

Even with a slow robot only able to execute 2 moves every second, it's easy to reach 12 seconds that way.

BTW, the human records are below the 10 seconds limit:
http://www.speedcubing.com/records/recs_cube_333av.html [speedcubing.com]
Average means that

• Re: (Score:2, Informative)

Just as a quick note, the page you linked is unofficial world records and hasn't been updated in a while. The official fastest times are here [worldcubeassociation.org]

Before someone claims dishonesty, all these solves were performed in competition with judges observing,
• LHC? (Score:2, Funny)

Am I the only one who thinks it looks a bit like ATLAS from the LHC??

Which makes it even more AWESOME.
• Direct link to video (Score:2)

Here's a direct link to the video, since the blog embedding it seems to be on the way to going down: CubeStormer [youtube.com]
• Heh that's nothing (Score:4, Insightful)

on Thursday February 18, 2010 @05:06PM (#31191982)

I have one I HAVEN'T solved in 30 years. Young kids, always wanting to do everything in a rush...

• Re: (Score:2)

I've solved one. But then my girlfriend gave me one with numbers instead of colours... Still haven't managed that one.
• Re: (Score:2)

I've solved one. But then my girlfriend gave me one with numbers instead of colours... Still haven't managed that one.

it's called sudoku.

• and here I was thinking..... (Score:2)

http://legorobotcomics.com/ [legorobotcomics.com]
• And how! (Score:3, Funny)

on Thursday February 18, 2010 @05:13PM (#31192046)

Once, I peeled off the three decals on the corner of a cube and stuck them in different places to try to stump it. It just peeled them back off and stuck them on in the right places.

~Loyal

• Wow. That site has more third party Javascript scr (Score:3, Informative)

<slashdot&spamgoeshere,calum,org> on Thursday February 18, 2010 @05:24PM (#31192180) Homepage
Wow. That site has more third party Javascript scripts included than I've ever seen. It scrolls off my screen when listed in NoScript. *That's* why NoScript is good. :)
• Simplified hardware (Score:3, Interesting)

on Thursday February 18, 2010 @05:49PM (#31192482)

This guy did it a while back with considerably less hardware, though it takes his rig a bit more time to get the puzzle done ;)

• I don't get it (Score:2, Interesting)

I can't understand why this is a "Lego" robot.
The pads are Lego the rest of the Lego is total cheap fluff. If I stick a few pieces of Lego on my car does that mean I drive a Lego car?
Maybe it is some cheap promo.

What am I missing here?

CC

• The computer driving it... (Score:2)

...should have been implemented as a difference engine constructed out of Legos. THEN I'm impressed.

• Bad news for the Chinese kids at the factory... (Score:2)

Now they'll have robots put the cubes in order for shipping. That's a lot of jobs...
• What? (Score:2)

It's made entirely of Legos. Except for the computer.

You know, I have a great Lego pizza oven. It's made entirely of Legos. Well, except for the metal box, heating element, wires, plug, and a few other things, of course. This is obviously some new use of the word "entirely".

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