Message #1061

From: Chris Locke <project.eutopia@gmail.com>
Subject: Re: [MC4D] 2-c parity(?) problem with 4^4
Date: Thu, 22 Jul 2010 13:48:07 +0900

Well, we can’t exactly solve it for you, but one of the big hints that
Brandon just gave is to try to "swap two indistinguishable pieces". When
you realize the presence of indistinguishable pieces, it suddenly no longer
becomes a parity issue, but just another case to work out with your
3-cycles. Still some work left for you to figure out exactly how to use the
3 cycles to get what you want done, but I think you’ll feel pretty good
about it when you do figure it out. Good luck!

Chris

2010/7/22 deustfrr <deustfrr@yahoo.ca>

>
>
> I updated the pictures. The red line is the wrong piece and the green line
> are the right pieces. And, can you make a log file showing the XY moves?
>
>
> — In 4D_Cubing@yahoogroups.com <4D_Cubing%40yahoogroups.com>, Brandon
> Enright <bmenrigh@…> wrote:
> >
> > —–BEGIN PGP SIGNED MESSAGE—–
> > Hash: SHA1
> >
> > On Wed, 21 Jul 2010 13:53:56 -0000
> > "deustfrr" <deustfrr@…> wrote:
> >
> > > I have a problem with the last 2 faces
> > >
> http://groups.yahoo.com/group/4D_Cubing/photos/album/346940124/pic/list
> > > reply please
> > > (I got parental controls on time so I just type that, lolz)
> > >
> >
> > deustfrr,
> >
> > Your images are quite hard (for me) to see the exact problem in context.
> >
> > However, for your "1-c piece situation" image, you have what appears to
> > be a blue and an orange 1-c central piece swapped. If you were solving
> > purely intuitively then you may have a bit of trouble solving this but
> > if you have a 3-cycle for the 1-c pieces then just swap two
> > indistinguishable pieces such as two blue in the 3-cycle along with the
> > orange.
> >
> > For your "2-c piece parity 1b" and "2-c piece parity 1a" images, this
> > isn’t really a parity but they must be solved together.
> >
> > I recently discussed a semi-generic technique for doing this on almost
> > any puzzle here:
> >
> http://www.twistypuzzles.com/forum/viewtopic.php?f=8&t=7830&p=219422#p219422
> > The general idea is to 3-cycle your two flipped pieces along with some
> > other (choice is arbitrary) piece such that one of the flipped pieces
> > moves into the place of the other flipped piece (call this sequence X).
> > Then flip the whole group over and put it back in place (call this Y),
> > then undo X, then undo Y. This technique will work in any number of
> > dimensions.
> >
> > Good luck,
> >
> > Brandon
> >
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>
>
>