Thread: "24-cell solved"

From: "Andrey" <andreyastrelin@yahoo.com>
Date: Wed, 16 Nov 2011 00:46:34 -0000
Subject: 24-cell solved



Finally I've got some time to work on 24-cell. Solve was easy enough until =
the last step (6C pieces) where I discovered that my ideas of moving them d=
on't work: I can't find easy operations that move 6C and don't move sub-cor=
ners. But it happened that my operations for moving sub-corners don't move =
corners! So I returned to the start of sub-corner positioning step and star=
ted to work on 6C instead.
Total twist count (after optimization) is 21137. Half of them (10606) was=
spent on first 4 steps, and second half - on last two. The longest operati=
on (3-cycle of 6C) was 139 twists long.
And I was lucky that I didn't meet parity problem at the end of 3C pieces=
stage: elementary twist of the cell gives even permutation of central 2C, =
but odd permutations of 3C and 6C. So it's possible that you'll need to re-=
solve eight 2C pieces when you think that you've done with them long time a=
go :)

Andrey




From: "schuma" <mananself@gmail.com>
Date: Wed, 16 Nov 2011 01:09:00 -0000
Subject: Re: 24-cell solved



Congratulations!

I pull out my notes, and find my order different. My order is: 2C faces, 3C=
edges, 6C corners, and then 1C inner corners, and the last step is 2C side=
-face pieces.=20

Before solving, I prepared a long macro for fixing the parity issue you men=
tioned, so that even if it occurs I'm not upset.=20

I'm wondering what is the "optimization" about the number of twists?

Nan

--- In 4D_Cubing@yahoogroups.com, "Andrey" wrote:
>
> Finally I've got some time to work on 24-cell. Solve was easy enough unti=
l the last step (6C pieces) where I discovered that my ideas of moving them=
don't work: I can't find easy operations that move 6C and don't move sub-c=
orners. But it happened that my operations for moving sub-corners don't mov=
e corners! So I returned to the start of sub-corner positioning step and st=
arted to work on 6C instead.
> Total twist count (after optimization) is 21137. Half of them (10606) w=
as spent on first 4 steps, and second half - on last two. The longest opera=
tion (3-cycle of 6C) was 139 twists long.
> And I was lucky that I didn't meet parity problem at the end of 3C piec=
es stage: elementary twist of the cell gives even permutation of central 2C=
, but odd permutations of 3C and 6C. So it's possible that you'll need to r=
e-solve eight 2C pieces when you think that you've done with them long time=
ago :)
>=20
> Andrey
>




From: "Andrey" <andreyastrelin@yahoo.com>
Date: Wed, 16 Nov 2011 01:28:35 -0000
Subject: Re: 24-cell solved



Nan,
"Optimization" is an item in "Edit" menu. It combines sequential twists a=
round the same axis, and removes pairs of opposite twists.
For example, if you apply this feature to your solve of 24cell, it'll red=
uce number of twists from 54199 to 35819 :)

Andrey

--- In 4D_Cubing@yahoogroups.com, "schuma" wrote:
>
> Congratulations!
>=20
> I pull out my notes, and find my order different. My order is: 2C faces, =
3C edges, 6C corners, and then 1C inner corners, and the last step is 2C si=
de-face pieces.=20
>=20
> Before solving, I prepared a long macro for fixing the parity issue you m=
entioned, so that even if it occurs I'm not upset.=20
>=20
> I'm wondering what is the "optimization" about the number of twists?
>=20
> Nan
>=20
> --- In 4D_Cubing@yahoogroups.com, "Andrey" wrote:
> >
> > Finally I've got some time to work on 24-cell. Solve was easy enough un=
til the last step (6C pieces) where I discovered that my ideas of moving th=
em don't work: I can't find easy operations that move 6C and don't move sub=
-corners. But it happened that my operations for moving sub-corners don't m=
ove corners! So I returned to the start of sub-corner positioning step and =
started to work on 6C instead.
> > Total twist count (after optimization) is 21137. Half of them (10606)=
was spent on first 4 steps, and second half - on last two. The longest ope=
ration (3-cycle of 6C) was 139 twists long.
> > And I was lucky that I didn't meet parity problem at the end of 3C pi=
eces stage: elementary twist of the cell gives even permutation of central =
2C, but odd permutations of 3C and 6C. So it's possible that you'll need to=
re-solve eight 2C pieces when you think that you've done with them long ti=
me ago :)
> >=20
> > Andrey
> >
>




From: Melinda Green <melinda@superliminal.com>
Date: Tue, 15 Nov 2011 18:33:13 -0800
Subject: Re: [MC4D] Re: 24-cell solved



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Now we have more than just Nan on the boards for the MPUlt puzzles! Yea!
The 24-cell appears to have not disappointed those who have only dreamed
of it for so long. I hope to see more names on the 24-cell HOF
soon, and I'd
really love to see a healthy competition for the shortest solution. I'm
guessing that 10k twists is within reason. What will it mean to
eventually tame this beast? Is there anything more to learn here that
the other puzzles haven't given us?

Thanks for this special puzzle, Andrey, and congratulations on your
latest solution.
-Melinda

On 11/15/2011 5:28 PM, Andrey wrote:
> Nan,
> "Optimization" is an item in "Edit" menu. It combines sequential twists around the same axis, and removes pairs of opposite twists.
> For example, if you apply this feature to your solve of 24cell, it'll reduce number of twists from 54199 to 35819 :)
>
> Andrey
>
> --- In 4D_Cubing@yahoogroups.com, "schuma" wrote:
>> Congratulations!
>>
>> I pull out my notes, and find my order different. My order is: 2C faces, 3C edges, 6C corners, and then 1C inner corners, and the last step is 2C side-face pieces.
>>
>> Before solving, I prepared a long macro for fixing the parity issue you mentioned, so that even if it occurs I'm not upset.
>>
>> I'm wondering what is the "optimization" about the number of twists?
>>
>> Nan
>>
>> --- In 4D_Cubing@yahoogroups.com, "Andrey" wrote:
>>> Finally I've got some time to work on 24-cell. Solve was easy enough until the last step (6C pieces) where I discovered that my ideas of moving them don't work: I can't find easy operations that move 6C and don't move sub-corners. But it happened that my operations for moving sub-corners don't move corners! So I returned to the start of sub-corner positioning step and started to work on 6C instead.
>>> Total twist count (after optimization) is 21137. Half of them (10606) was spent on first 4 steps, and second half - on last two. The longest operation (3-cycle of 6C) was 139 twists long.
>>> And I was lucky that I didn't meet parity problem at the end of 3C pieces stage: elementary twist of the cell gives even permutation of central 2C, but odd permutations of 3C and 6C. So it's possible that you'll need to re-solve eight 2C pieces when you think that you've done with them long time ago :)
>>>
>>> Andrey
>>>
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>

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Now we have more than just Nan on the boards for the MPUlt puzzles!
Yea! The 24-cell appears to have not disappointed those who have
only dreamed of it for so long. I hope to see more names on the href="http://wiki.superliminal.com/wiki/MPUlt_24-cell_Puzzles">24-cell
HOF soon, and I'd really love to see a healthy competition for
the shortest solution. I'm guessing that 10k twists is within
reason. What will it mean to eventually tame this beast? Is there
anything more to learn here that the other puzzles haven't given us?



Thanks for this special puzzle, Andrey, and congratulations on your
latest solution.

-Melinda



On 11/15/2011 5:28 PM, Andrey wrote:


Nan,
"Optimization" is an item in "Edit" menu. It combines sequential twists around the same axis, and removes pairs of opposite twists.
For example, if you apply this feature to your solve of 24cell, it'll reduce number of twists from 54199 to 35819 :)

Andrey

--- In 4D_Cubing@yahoogroups.com, "schuma" <mananself@...> wrote:



Congratulations!

I pull out my notes, and find my order different. My order is: 2C faces, 3C edges, 6C corners, and then 1C inner corners, and the last step is 2C side-face pieces.

Before solving, I prepared a long macro for fixing the parity issue you mentioned, so that even if it occurs I'm not upset.

I'm wondering what is the "optimization" about the number of twists?

Nan

--- In 4D_Cubing@yahoogroups.com, "Andrey" <andreyastrelin@> wrote:



Finally I've got some time to work on 24-cell. Solve was easy enough until the last step (6C pieces) where I discovered that my ideas of moving them don't work: I can't find easy operations that move 6C and don't move sub-corners. But it happened that my operations for moving sub-corners don't move corners! So I returned to the start of sub-corner positioning step and started to work on 6C instead.
Total twist count (after optimization) is 21137. Half of them (10606) was spent on first 4 steps, and second half - on last two. The longest operation (3-cycle of 6C) was 139 twists long.
And I was lucky that I didn't meet parity problem at the end of 3C pieces stage: elementary twist of the cell gives even permutation of central 2C, but odd permutations of 3C and 6C. So it's possible that you'll need to re-solve eight 2C pieces when you think that you've done with them long time ago :)

Andrey










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