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 Post subject: Void parity
PostPosted: Mon Jan 20, 2014 11:53 pm 
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Joined: Thu Jan 16, 2014 8:35 pm
Can somebody tell me why a corner parity happens with the void 3x3?
This parity has puzzled me for a long time and I don't know how to get rid of it.
Somehow ONLY 2 corners are getting swapped and it happens occasionally. Even my other puzzle friends at school don't know why this happens with the void and not with a standard 3x3. Somebody help me please!


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 Post subject: Re: Void parity
PostPosted: Tue Jan 21, 2014 12:02 am 
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Joined: Thu Dec 31, 2009 8:54 pm
Location: Bay Area, California
The fact that corners are swapped and not edges is an artifact of your solve order. You must solve corners last.

Anyways, on the void-cube a middle-slice changes the parity of the edges without changing the parity of the corners. Do a quarter-turn of the top face which does a 4-cycle of corners and edges. This will fix the parity in the corners and break the parity in the edge. Then do a middle slice turn which will fix the parity in the edges. You will be a few pure, even-cycles from solved.

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 Post subject: Re: Void parity
PostPosted: Tue Jan 21, 2014 12:49 am 
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For mine, I typically just make and M' move, (or the slice between L and R up) and then replace the two bottom edges I just disturbed, and finally resolving the puzzle.

If you want an actual algorithm for than, I'll do my best

(M' U M' U' M) Y2 (M' U' M' U2 M)

Then solve like normal, Y is a horizontal rotation of the entire puzzle about the U/D axis in case anyone was wondering.


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 Post subject: Re: Void parity
PostPosted: Tue Jan 21, 2014 12:51 am 
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Joined: Thu Jan 16, 2014 8:35 pm
Thanks guys!


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 Post subject: Re: Void parity
PostPosted: Tue Jan 21, 2014 2:47 pm 
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Joined: Tue Aug 11, 2009 2:44 pm
You can also do this on the Mixup Cube; it's a bit harder to fix there.


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 Post subject: Re: Void parity
PostPosted: Tue Jan 21, 2014 3:42 pm 
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bhearn wrote:
You can also do this on the Mixup Cube; it's a bit harder to fix there.

I have a pretty cool sequence to fix this on the Mixup cube. First I used setup moves to put all edges in the right orientation into the 4 center spots so that a single slice is an 8-cycle of edges which fixes the parity. Then I undo the prepatory setup moves which leaves the puzzle in the cube shape and then I undo the resulting cycle in the edges which is a nice symmetrical sequence.

I could dig up my Mixup Cube and demo this if anyone is interested.

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 Post subject: Re: Void parity
PostPosted: Tue Jan 21, 2014 4:22 pm 
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Joined: Thu Mar 28, 2013 7:14 pm
Why does this happen on void puzzles but not the standard 3x3?


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 Post subject: Re: Void parity
PostPosted: Tue Jan 21, 2014 4:30 pm 
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Hi Brandon, I'd like to see your sequence, mine's here https://www.youtube.com/watch?v=PdCVazEZtg8 at 12:53.

rplass, it's because there's no specific position for the `missing` centre pieces, so it's possible to solve it with a 90* twist `out` on a slice layer. Try solving your RC with the centres in the E slice all 1 step around to see it :) .

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1st 3x3 solve Oct 2010 (Even though I lived through the 80s).
PB 3x3 55sec Jan 2011 (When I was a kid 1:30 was speedcubing so I'm stoked).
1st 3x3 Earth (nemesis) solve Jan 2011 My You Tube (Now has ALLCrazy 3X3 Planets with Reduction)


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