From cube-lovers-errors@mc.lcs.mit.edu Tue Sep 30 18:10:34 1997
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Mail-from: From roger.broadie@iclweb.com Tue Sep 30 18:05:38 1997
From: roger.broadie@iclweb.com (Roger Broadie)
To:
Subject: Re: 4x4x4 solution
Date: Tue, 30 Sep 1997 23:02:48 +0100
Message-Id: <19970930230037.AAA21244@home>
C.McCaig@queens-belfast.ac.uk wrote:
> ...I recently borrowed a friends 4x4x4, and I ... can't figure out a
> move for reorientating the single edge pair....
It is possible to solve the problem with a sequence based on a quarter
turn of a central slice, since that, like a swap of two edge pieces,
involves an odd-parity cycle of the edge pieces. Thus
r2 U2 r U2 r2
(where r is the turn of the inner slice next to R in the direction
parallel to R)
puts a 4-cycle of edges onto the top face, but leaves you with the task
of restoring the centres.
It was the desire to find something less cumbersome that first lead me
to investigate the archives of this list, and there the answer was:
Date: Fri, 20 Oct 95 12:46:32 -0400 (EDT)
From: Georges Helm
Subject: Re: Old question about 2 adj edges
how to flip 2 adj. edges (and nothing else) in 4x4x4 cube?
r^2 U^2 r l' U^2 r' U^2 r U^2 r l U^2 l' U^2 r U^2 l r^2 U^2
Georges
geohelm@pt.lu
It does indeed contain an odd number of turns of the central slices to
give the desired parity.
Roger Broadie