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Re: [Speed cubing group] Re: Working on learning a 3-look LL

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  • Dan Harris
    I would like to suggest two slightly different algorithms for these cases, then you can make a choice as which ones you like best. For the double-sune case
    Message 1 of 1 , Sep 5 7:36 AM
      I would like to suggest two slightly different algorithms for these cases,
      then you can make a choice as which ones you like best.

      For the "double-sune" case the fast and very easily remembered F (R U R' U'
      R U R' U' R U R' U') F' = F (R U R' U')*3 F' is a nice algorithm. This is
      what I think is an order-2 alg, so do it once and you get the case, do it
      twice and you get back to where you started.

      For the "bruno", I would suggest the inverse of Doug's algorithm, but this
      time there isn't that much to choose between them. But when performing R U2
      R2 U' R2 U' R2 U2 R' - it can all be done in one fluid motion, as there is
      more scope for using the left index finger to make the U' whilst the right
      hand is working on the R2's Once you get your left and right hands working
      in time with each other, this alg can be very fast indeed. The R2 U2 R' at
      the end is quite tough however.

      Good Luck in learning them all!

      DanH :)

      ----- Original Message -----
      From: "d_funny007" <no_reply@yahoogroups.com>
      To: <speedsolvingrubikscube@yahoogroups.com>
      Sent: Friday, September 05, 2003 3:14 PM
      Subject: [Speed cubing group] Re: Working on learning a 3-look LL


      > Simple solution to your 4 corners twisted problem: double-sune and
      > bruno (R'U2R2UR2UR2U2R'). DanK/Mirek's Z Perm is the way to go, look
      > up DanK video on it... so you don't end up getting a bad habit of
      > the brute force alg.
      >
      > I'm going through the same phase, teaching a friend of mine that's
      > at about 50s. (Just last night planning how to line up the next 8
      > PLLs: he knew the 3 edge ones, so I gave him the T and Y to start
      > off with... A and V might be the next step).
      >
      > -Doug
      >
      >
      > --- In speedsolvingrubikscube@yahoogroups.com, jasmine_ellen
      > <no_reply@y...> wrote:
      > > What a very detailed reply Ryan!
      > >
      > > Here's where I'm up to at the moment... I've learnt several LL
      > edge
      > > algs -- ones that mess with the corners (which doesn't matter if
      > LL
      > > edges are oriented first). I already knew several LL edge algs
      > that
      > > preserve the corners -- I guess these are useful if the corners
      > are
      > > already done when you get to the LL.
      > >
      > > I already know the Sune and its mirror (can't imagine there'd be
      > any
      > > cuber who doesn't know this alg?!). I've learnt the algs for the
      > > three LL corner orientation positions where 2 are corrent and 2
      > > require twisting. Still need to learn the 2 algs for when all 4
      > > require twisting.
      > >
      > > I'm aiming to learn the 13 PLL if my enthusiasm lasts that long.
      > In
      > > case it doesn't, I planned the order that I would learn the algs.
      > > First I revised the algs that just move the edges since. I knew U
      > and
      > > H, but for some reason was a bit iffy with Z. After that, I just
      > > ranked them by 'probability of occurrence'. So, of the remaining
      > 10,
      > > I've memorised the algs with a frequency of 1/9 or greater (A, R,
      > J,
      > > G). So, 7 down, 6 more to go.
      > >
      > > I think I need to take a break from new algs and spend some time
      > > getting the newly memorised algs firmly planted in my head. I'm
      > > finding that I can remember them without a problem, but I'm still
      > > taking a bit of time recognising the patterns. I'm not concerned
      > > though because I know that practise will fix this!
      > >
      > > Jasmine.
      > >
      > > --- In speedsolvingrubikscube@yahoogroups.com, Ryan Heise
      > > <rheise@p...> wrote:
      > > > On Mon, Sep 01, 2003 at 11:48:01AM -0000, jasmine_ellen wrote:
      > > > > I remembered that DanK had something like this on his site
      > about
      > > a
      > > > > beginner method, an intermediate method and an advanced
      > method.
      > > This
      > > > > is actually what I was after. Who else has something like this
      > on
      > > > > their site?
      > > >
      > > > I'll describe the beginner and intermediate methods that I once
      > > used.
      > > > They are simplications of the Fridrich last layer system. You
      > need
      > > to
      > > > first understand how that system works:
      > > >
      > > > http://www.ws.binghamton.edu/fridrich/system.html#last
      > > >
      > > > This general strategy, orienting first, then permuting, is good
      > > because
      > > > it is very easy to recognise the positions quickly. But instead
      > of
      > > > orienting all the pieces at once, you just orient the edges
      > first,
      > > and
      > > > the corners second.
      > > >
      > > > BEGINNER METHOD
      > > >
      > > > First, orient the 4 edges (ie. make a cross). There are only 4
      > > patterns,
      > > > and one algorithm to solve them all! To view this, you need to
      > use a
      > > > fixed width font:
      > > >
      > > > --- --- -x- -x-
      > > > -x- xxx xx- xxx
      > > > --- --- --- -x-
      > > >
      > > > For each pattern, apply the algorithm "R'U'F'U F R" and it will
      > > take you
      > > > to the next pattern. Eventually you will end up with a cross.
      > > >
      > > > Improvement: notice that if you apply the algorithm when you
      > already
      > > > have the cross, you will end up with a line. That means that you
      > can
      > > > jump immediately from the 2nd pattern to the 4th pattern by
      > > applying the
      > > > algorithm backwards! So, this step should take an average of 6
      > > moves.
      > > >
      > > > Next, orient the corners. There are only 6 patterns apart from
      > > solved.
      > > > Look through this complete list, and find all the patterns (and
      > > > algorithms) that have a cross already formed:
      > > >
      > > > http://www.ws.binghamton.edu/fridrich/Mike/orient.html
      > > >
      > > > For the case when 3 corners need to be twisted, I recommend the
      > > Sune TM
      > > > algorithm from Petrus. See the applet at the top/right of his
      > page:
      > > >
      > > > http://lar5.com/cube/fas6.html
      > > >
      > > > I think it's useful to learn to twist them forwards and
      > backwards:
      > > >
      > > > - R U R'U R U2 R'
      > > > - R'U'R U'R'U2 R
      > > >
      > > > To see that done fast, have a look at the quicktime movies at
      > the
      > > bottom
      > > > of this page:
      > > >
      > > > http://lar5.com/cube/speed.html
      > > >
      > > > I recommend this algorithm because one of the other orientation
      > > cases
      > > > can be solved by just applying this algorithm twice. To know
      > which
      > > case
      > > > I'm talking about, apply this to a solved cube:
      > RU2R'U'RUR'U'RU'R'.
      > > >
      > > > Now, apply the sune (RUR'URU2R') twice:
      > > >
      > > > RUR'URU2R' + RUR'URU2R'
      > > >
      > > > Notice that the moves in the middle cancel out? So you can
      > actually
      > > do:
      > > >
      > > > RUR'URU'R'URU2R'
      > > >
      > > > which is an "optimal" solution.
      > > >
      > > > Next, permute the corners (yes, before the edges). Most of the
      > time
      > > > there will be a 3 cycle of corners. In this case, look at the 4
      > > sides of
      > > > the last layer. On one of the sides, the two last layer corners
      > > will be
      > > > matching in colour. Hold those two corners on the back side and
      > do:
      > > >
      > > > R'FR' B2 RF'R' B2 R2
      > > >
      > > > Now the corners should be solved. If you don't find any two
      > corners
      > > that
      > > > match, apply the above algorithm and that should result in a
      > > position
      > > > where two corners match. Don't worry, this case rarely happens.
      > If
      > > you
      > > > want, you can learn a special algorithm for that case by picking
      > the
      > > > most attractive one from:
      > > >
      > > > http://www.ws.binghamton.edu/fridrich/Mike/permute.html
      > > >
      > > > The "Y" pattern on that page has the desired corner effect.
      > > >
      > > > Next, permute the edges. Again, most of the time, there will be
      > a 3
      > > > cycle of edges. You need to learn to cycle the edges forwards and
      > > > backwards:
      > > >
      > > > - R2U FB'R2F'BU R2
      > > > - R2U'FB'R2F'BU'R2
      > > >
      > > > Sometimes, all 4 edges need to be swapped in opposite pairs.
      > That's
      > > an
      > > > easy case, so why not learn it:
      > > >
      > > > RLU2R'L' [U] R'L'U2RL
      > > >
      > > > The [U] means rotate the whole cube from the up side, 90 degrees.
      > > >
      > > > There's also a rare case where all 4 edges need to be swapped in
      > > > adjacent pairs. The algorithm's difficult so it's not worth
      > > learning.
      > > >
      > > > INTERMEDIATE METHOD
      > > >
      > > > First, orient everything like the beginner method. Then permute
      > > > everything like the full blown Fridrich method.
      > > >
      > > > How can you learn all the permutations? See my previous email:
      > > >
      > > > c
      > > >
      > > > There, I list which algorithms to learn first, and which
      > algorithms
      > > to
      > > > learn last.
      > > >
      > > > ADVANCED METHOD
      > > >
      > > > You already know enough! It is not necessary to learn 40
      > orientation
      > > > algorithms. 6 is enough. Gilles Roux proved that it is possible
      > to
      > > > achieve sub-20 times with just these 6 orientation algorithms
      > and 13
      > > > permutation algorithms. He used the petrus method for the first
      > two
      > > > layers which gives you a cross automatically when you get to the
      > > last
      > > > layer. Using that strategy, those extra orientation algorithms
      > are
      > > not
      > > > needed.
      > > >
      > > > Ryan
      >
      >
      >
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