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Thistlethwaite, human version

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  • Ryan Heise
    Over the past few years, I have been exploring new ways of solving the cube. I pretty much stopped speed cubing during this period, and just continued
    Message 1 of 1 , Jul 1, 2003
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      Over the past few years, I have been exploring new ways of solving the
      cube. I pretty much stopped speed cubing during this period, and just
      continued experimenting until I found a system I was willing to commit
      to. This is not it, but Ron suggested that I describe it to you all
      anyway. I have a habit of only revealing the systems that I have no
      intention of using (for instance, "tripod"). After all, I don't want to
      give my competitors the advantage :-)

      As I said, this system requires no thinking. All solutions to all cases
      can be memorised and applied, with an end result of maybe 13 seconds
      average. Maybe someone is interested in doing that. Personally, I find
      it hard to call that puzzle solving - it's more like running the 100
      metres.

      (btw, I am not competing in this year's championships so people have
      suggested that I reveal the system I actually use- I agree. Stay tuned.)

      ----- Forwarded message from Ryan Heise <rheise@...> -----

      From: Ryan Heise <rheise@...>
      Date: Sun, 22 Jun 2003 11:30:52 +1000
      To: Ron van Bruchem <rvb@...>
      Subject: Thistlethwaite, human version

      On Sat, Jun 21, 2003 at 06:13:28PM +0200, Ron van Bruchem wrote:
      > Hi Ryan,
      >
      > I am very interested in the ideas you have.
      > Please tell me something about the systems you came up with, and how many
      > algorithms you need per stage.

      Phase 1 -> <U,D,L,R,F2,B2> group

      - simple, no algorithms

      Phase 2 -> <U,D,L2,R2,F2,B2> group

      - Direct up/down edges to up/down face (simple, no algs)
      - Direct corners to up/down face (between 8 and 60 algs)

      Phase 3 -> <U2,D2,L2,R2,F2,B2> group

      - Corners (between 1 and 2 algs)
      - Edges (between 1 and 4 algs)

      Phase 4 -> place pieces

      - Corners (intuitive)
      - Edges (intuitive)

      DETAILS OF STEPS

      * PHASE 1

      This is solved in 4.6 moves on average.

      * PHASE 2 EDGES

      This is rather simple. You can learn all 20-30 cases if you wish. I
      forget the exact number. This can be solved in an average of 4 moves.

      * PHASE 2 CORNERS

      I used a method similar to Gaetan - first get 3 corners oriented on one
      side, and then apply one of 8 algorithms. It is possible to directly
      learn all 60 cases if you want (I can't remember the exact number).
      I think they have an average of 8.5 moves.

      * PHASE 3 CORNERS

      In phase 3, it is important to do the corners first, because it is
      difficult to see whether they have made it into the U2D2L2R2F2B2 group.
      Just getting opposite colours on each side isn't enough. The algorithms
      you learn to fix this are shorter when you don't have to worry about the
      edges.

      Here, I'll just describe the simplest technique that requires two
      algorithms, but is very quick for the fingers and brain:

      First, separate up/down colours (one colour on each side). Average 3.2
      moves. There should be, for example, all red corners on top, and all
      orange corners on bottom.

      Now, pairs of adjacent corners will either match or mismatch. Our goal
      is to make them either all match, or all mismatch. So, in this step, we
      find the odd pairs out (whether they're matching or mismatching), and
      fix them so they match/mismatch like all the rest. There are 4 pairs.
      Either one pair is the odd one out, or two pairs are the odd ones out.

      For one pair: hold the pair at UF, and do R'FR'B2RF'R. It's a
      modification of the corner mover that doesn't care about the exact
      positions of corners.

      Two pairs: hold two pairs on F (you may need to move them there), and do
      R2UF2U2R2U. (if you needed to move them there first, there's also a
      trick to get it to work...)

      I looked for a long time to find other methods here that used fewer
      moves. I found some, but this way was definitely by far the quickest to
      perform.

      PHASE 3 EDGES

      4 cases - simple (2,4,6 or 8 bad edges). Average 6.1 moves.

      Total moves so far: 33.4. Obviously, fewer moves are necessary to
      achieve an average of 40 moves overall. I worked out some shortcuts, but
      I don't think they're worth it, because I could perform the longer way
      faster.

      PHASE 4 (the end game)

      I think you already have a strategy for this. Corners, then edges. I
      think it's possible to learn all cases for the edges (about 150 I think,
      but easy to memorise).

      A downside is the number of double turns which are more difficult to
      perform. But I tried a few algorithms and they are possible to do
      quickly enough. I think the main benefit of this method is fast reaction
      time and no thinking. Another benefit is that it looks cool when you
      solve it. None of the pieces are placed until the very end.

      Above, I listed each individual step with no shortcuts. It is possible
      to combine steps, or do steps in different orders depending on
      opportunities. The basic method above, if you learnt all cases for each
      exact step, should give an average of 45.7 moves.

      Ryan

      ----- End forwarded message -----

      Just a note I'd like to add: it is not necessary to stick to only moves
      within each group. For example, in phase 4, it is not necessary to stick
      to double turns. In fact, the shortest solutions for most cases involve
      single turns. The first half (phases 1-2) already has a lot of freedom
      of movement. I suppose it could be solved in 5 to 6 seconds. Maybe
      someone has a better way to finish phases 3-4? For example, one idea is
      to first get all red on top, and all orange on bottom, then permute.
      Another idea is to build up blocks like Fridrich and Petrus (more
      intuitive).

      Ryan
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