Message #1060

From: deustfrr <deustfrr@yahoo.ca>
Subject: Re: [MC4D] 2-c parity(?) problem with 4^4
Date: Wed, 21 Jul 2010 23:48:17 -0000

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, Brandon Enright <bmenrigh@…> wrote:
>
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> 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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