Why It's Almost Impossible to Solve a Rubik's Cube in Under 3 Seconds

[Waldo 96]

I remember having a Rubik's Cube as a kid; IIRC, once or twice I solved it around 40 or 50 seconds. Anyhow, just came across this on YouTube...

 

 

Also, I find the part about 'God's Number' very interesting, like, what's the most computationally efficient / optomised way to calculate it?...

[Waldo 96]

More on God's Number...

 

https://ruwix.com/the-rubiks-cube/gods-number/

[ez8004 10]

Solved in 0.637s in 2016. Machines are taking over. 

[Waldo 96]

9 hours ago, ez8004 said:

Solved in 0.637s in 2016. Machines are taking over. 

A machine in the video above, solves it in .25 of a second. Frightening!

 

With a machine, the limiting factor will be the mechanical element, how fast it can manipulate the cube. In the video, the chinese lady was saying for her, the limiting factor is actually the calculation part, figuring out which 'algorithms' to use to solve, rather than hand speed.

Edited May 30, 2019 by Waldo

[Dozer 13]

None of this is very good for my self-esteem.

 

[Baron99 778]

40 years & counting.  

 

We thought one of our children was good at it until we caught him just swapping the the coloured stickers around. 

[Waldo 96]

2 minutes ago, Baron99 said:

40 years & counting.  

 

We thought one of our children was good at it until we caught him just swapping the the coloured stickers around. 

My dad was also caught! He actually had dismantled and reassembled it...

[Baron99 778]

5 hours ago, Waldo said:

My dad was also caught! He actually had dismantled and reassembled it...

For me the Rubik's Cube is up there with suduko.  Life's too short. 

 

My excuse anyway. 

[*_ash_* 88]

On 29/05/2019 at 22:43, Waldo said:

I remember having a Rubik's Cube as a kid; IIRC, once or twice I solved it around 40 or 50 seconds. Anyhow, just came across this on YouTube...

 

 

Also, I find the part about 'God's Number' very interesting, like, what's the most computationally efficient / optomised way to calculate it?...

On 30/05/2019 at 21:33, Baron99 said:

For me the Rubik's Cube is up there with suduko. 

 

Life's too short. 

 

My excuse anyway. 

cocked up the quotes, sorry. I can't get them to work right these days. I thought I'd post though, as a little story of me and the cube (not particularly interesting   but hey ho) you're both long standing members so perhaps might read.

 

waldo: can you still do it?

If you got to 40 or 50 seconds you must have mastered it (how long ago?). I wondered if you ever forget?

 

-----

 

Baron99, I posted because of this post!

 

I too remember having a go as a kid, but it was my brother's, so I think it might have been out of bounds.

 

Fast forward 30 years or so and was at a friend's house for the evening. I noticed one on the sideboard, when lad was taking a leak... his wife said, oh don't mess that up, he's spent ages on it. I can't recall which order all this happened (ironically), however the short answer is, I messed it up!

 

so I took it home, printed the instruction manual, and spent all sunday afternoon outside at my parents house (too noisy in my flat) trying to work it out. Perhaps 4-6 hours or so for first time. Once memorized the stages, some easier than others, I soon could do it in about 10 minutes. Then after making the cube easier to turn and practised a bit, I could almost always do it the 90-180 seconds, then almost always under a minute. However, using the instructions, it limits the speed capability. If you could a graph it would be a bizarre one, as once you learn it, the time comes rapidly down (or did for me anyway), then you become limited. I then looked at youtube and saw lots of new ways, to make faster, but this is where I was at the stage you mention (life's too short / or in my case, I just thought why bother? I was shocked over time when they came back in fashion how amazed if I didn't tell them, and solved it while they were making a cup of tea or something. It can be used as a party trick.

Fastest I've done is around 20-30 seconds, and I've just had a go now, after maybe a year of not doing it, and still can do 3 mins.

 

Some other things that I thought of Baron/waldo at your posts, and why I posted.

 

1. Coincidentally Baron, I like Sudoko (and the sunday times is worth buying just for the train logic game on sundays!)

2. They are very different though. The big difference is sudoku requires logic only, whereas the cube requires knowledge of it, AND the logic of how to do it. 

3. I think people like doing crosswords and that, for similar reason. It's enjoyable. And a mental exercise.

4. The next time I saw friends, I showed them that I could do it, and they were impressed. He was astounded and perhaps thought I was a genius! - then I told him I used the instructions, and he said 'ah you cheat, I thought you learned how to do it!' - I was gutted! It took a lot of work!

 

last thing, 5. At anyone, with point 4, does anyone know how many people can solve it without instruction manual? I wonder.

 

edit to add: 6. It's also good for winning bets. I've won a couple!

 

 

 

 

 

Edited June 9, 2019 by *_ash_*

[Waldo 96]

Hi Ash,

 

This was like 30+ years ago for me. Solving it under a minute was rare for me; but this one time I did it while walking through a car park in Skegness with my parents and a couple of their friends. I must have been a 15-ish, maybe. I was playing around with a cube and my dad was telling his friend I could do it; and I was saying "yeah, in around a minute". My dad's friend just didn't believe it, and so he mixed it up and as we walked I solved it pretty quick. I remember him saying, even though he's just seen it, he still didn't believe it! Which very much amused me. There wasn't any great skill to it, just remembering around 10 or 12 different patterns (that I had on a photocopied sheet of A4) to solve the cube in stages.

 

I've not touched one in decades, and there's no way I'd remember how to do one now. Tempted to get one though, just out of curiosity.

Edited June 10, 2019 by Waldo

[*_ash_* 88]

1 hour ago, Waldo said:

Hi Ash,

 

This was like 30+ years ago for me. Solving it under a minute was rare for me; but this one time I did it while walking through a car park in Skegness with my parents and a couple of their friends. I must have been a 15-ish, maybe. I was playing around with a cube and my dad was telling his friend I could do it; and I was saying "yeah, in around a minute". My dad's friend just didn't believe it, and so he mixed it up and as we walked I solved it pretty quick. I remember him saying, even though he's just seen it, he still didn't believe it! Which very much amused me. There wasn't any great skill to it, just remembering around 10 or 12 different patterns (that I had on a photocopied sheet of A4) to solve the cube in stages.

 

I've not touched one in decades, and there's no way I'd remember how to do one now. Tempted to get one though, just out of curiosity.

Hi. Yes, I found that people always think I'm cheating to do it.

 

Like you say, once learned the stages it's not difficult.  It does take effort though to learn moves in first place. In the film it says nowadays there are cubes that move easier. Sometimes I found ones at people's houses and they so hard to move it probably not good for your wrists and hands.

 

Edited June 10, 2019 by *_ash_*

[Waldo 96]

4 hours ago, *_ash_* said:

Hi. Yes, I found that people always think I'm cheating to do it.

 

Like you say, once learned the stages it's not difficult.  It does take effort though to learn moves in first place. In the film it says nowadays there are cubes that move easier. Sometimes I found ones at people's houses and they so hard to move it probably not good for your wrists and hands.

 

Also they mention there are more move combinations today, 50+ I think they said. In addition, sometimes an 11 move combo is faster than a 9 move combo (that both achieve the same end result) because the 11 move version is physically quicker to execute.

 

As far as the 'cheating' goes, I wouldn't say it's cheating at all, certainly not in the way that removing and re-applying all the stickers, or taking apart and reassembling the cube, would be! Also, it would be near impossible to work it our from scratch, without the use of any algorithms / combos. I could be wrong, but I seriously doubt anyone on the planet could do that!