Are you puzzled pedants?

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Are you puzzled pedants?

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1Novak
apr 29, 2014, 5:20 am

Copied from the BBC on-line newspage today.

Maximum number of face turns needed to solve Rubik cube - "God's number" - is 20. This proof was arrived at in 2010 by team of researchers led by Tomas Rokicki, a programmer from Palo Alto, California.

I must be pretty good, I can use far more than this “Maximum”.

2thorold
apr 29, 2014, 6:04 am

I think that makes sense if you think like a mathematician, but it's been compressed by a journalist from what was probably a clearer original text. The researchers presumably proved that, starting from any arbitrary configuration, if you make the most efficient possible move each time you never need more than 20 moves to solve the puzzle. Of course, that doesn't tell us what the most efficient next move actually is.

3JerryMmm
apr 29, 2014, 7:51 am

Which it says: "Maximum number of face turns needed to solve"

Seems clear?

4thorold
apr 29, 2014, 8:04 am

http://www.cube20.org/

Apparently the term "God's number" comes from the notion that this is the maximum number of moves an omniscient being (who of course has memorised all the optimum solutions) would need to solve the puzzle.

5krazy4katz
apr 29, 2014, 9:48 am

Shouldn't it be the minimum number needed to solve…

6jjwilson61
Bewerkt: apr 29, 2014, 11:53 am

No, because if the cube has been shuffled randomly it may be solved in one, or even zero, moves. It's saying that no matter what the initial state of the cube a perfect player will need at most 20 moves.

7krazy4katz
apr 29, 2014, 12:23 pm

Ah, the subtleties…
Thank you for the explanation.

8BoMag
apr 30, 2014, 1:40 am

Dit lid is geschorst van de site.

9thorold
apr 30, 2014, 3:07 am

>8 BoMag:
In 1980 everyone had a Rubik's cube.

10BoMag
apr 30, 2014, 6:04 am

Dit lid is geschorst van de site.

11thorold
apr 30, 2014, 7:10 am

(Resists the temptation to Photoshop a bit of the Sistine Chapel ceiling)

12BoMag
apr 30, 2014, 7:22 am

Dit lid is geschorst van de site.

13Noisy
apr 30, 2014, 7:28 am

14thorold
apr 30, 2014, 7:33 am

>12 BoMag:,>13 Noisy:
Both wrong. It should be "no more than twenty"

15BoMag
Bewerkt: apr 30, 2014, 7:59 am

Dit lid is geschorst van de site.

16BoMag
apr 30, 2014, 8:00 am

Dit lid is geschorst van de site.

17BoMag
Bewerkt: apr 30, 2014, 8:02 am

Dit lid is geschorst van de site.

18thorold
apr 30, 2014, 9:42 am

You can, but you have to enter it as an html entity (&lt;): < 20
But the value twenty is also possible, so it should be ≤ 20

19Novak
Bewerkt: apr 30, 2014, 2:41 pm

So........Instead of all that nonsense of:

Maximum number of face turns needed to solve Rubik cube - "God's number" - is 20.

What they mean is: The number of face turns needed to solve Rubik cube - is (less-than symbol) 20.

The Maximum/Minimum bit just confused everyone. And these are journalists?

>2 thorold: I think that makes sense if you think like a mathematician, but it's been compressed by a journalist......

So.. .. .. The number of turns is compressed to only 15? :)

20krazy4katz
apr 30, 2014, 2:53 pm

I'm outta here...

21Novak
apr 30, 2014, 4:14 pm

Wait for me................

22krazy4katz
apr 30, 2014, 6:08 pm

No way. Save yourself! ;-)

23Amtep
mei 2, 2014, 5:47 pm

Simpler: "The Rubik's cube can be solved in 20 or fewer moves no matter how scrambled it is, and there are some starting positions that require the full 20 moves."

24PhaedraB
mei 2, 2014, 11:32 pm

It takes me somewhere between 20 and a million. I've never solved one.

25Amtep
mei 3, 2014, 6:37 pm

Maybe you have one that can't be solved? Always blame the technology.

26PhaedraB
mei 4, 2014, 12:00 am

>25 Amtep: Good re-frame, thanks!

27Novak
mei 9, 2014, 5:29 am

The puzzle, surely, is to work it out for yourself. (I have not yet managed but I'm close.)

The idea of getting a video to learn how to do it is counter-productive.

28quintanar
Bewerkt: sep 11, 2014, 4:53 pm

Then GOD Had one back in those days.

29dtw42
sep 15, 2014, 2:58 pm

I saw the subject heading for this thread and vainly hoped it might be about crosswords. Hey ho. I'm with PhaedraB on this one: my parents bought me an unbranded knock-off Rubik's cube back in the 80s and I never managed to solve that. Because it wasn't a genuine jobbie I've never been sure whether my lack of success with it was down to my not-very-analytical brain, or it being unsolvable.

30Novak
sep 15, 2014, 3:15 pm

>29 dtw42: So.. .. .. You reckon the reason you couldn't do it was.. .. because it was a fake? Nice try. :)

31dtw42
sep 15, 2014, 4:26 pm

Yup. That's my excuse and I'm sticking to it.