Message #3931

From: Luna Peña <scarecrowfish@gmail.com>
Subject: Re: [MC4D] Physical 2x2x2x2 - Canonical moves
Date: Sat, 06 Jan 2018 02:07:56 +0000

OK. Given that, I’d say that:

1-5 are primitive.

7-8 are canonical.

(The rest of ROIL (as in, other twists of the centre 2x2x2 and the
restacked IO twists) may be canonical or may require labeling. I am
unsure.)

6&9(&10?) only with clear labeling (ie. counted as a separate kind of
solve, like macro vs non-macro in MC4D). 11 could possibly be included at a
stretch.

12 is unacceptable.

~Luna

On 6 Jan 2018 01:45, "Melinda Green melinda@superliminal.com [4D_Cubing]" <
4D_Cubing@yahoogroups.com> wrote:

Certainly.

#4 is a twist of the central 2x2x2 block about the long axis. It is a twist
of the face joining the two halves of the puzzle. It is equivalent to
twisting both end caps the opposite direction.

#5 is the first "compound move" that I talk about in the video here
<https://www.youtube.com/watch?v=_D4m1Kit3TI&t=1m39s> as a natural
consequence of combining simple rotations with 90 degree twists.

#7 is the fancy 4D change of projection described in the first link in the
description here <https://www.youtube.com/watch?v=d2Fh_1m0UVY>.

-Melinda

On 1/5/2018 9:54 AM, Luna Peña scarecrowfish@gmail.com [4D_Cubing] wrote:

Can I get clearer definitions of 4, 5 and 7?

~Luna

On 4 Jan 2018 23:28, "Melinda Green melinda@superliminal.com [4D_Cubing]" <
4D_Cubing@yahoogroups.com> wrote:

>
>
> First off, please check out Zander Bolgar’s lovely solution video
> <https://www.youtube..com/watch?v=fYxn4wPe2ZE> that he invited me to
> share. It’s very cool to see someone developing something like finger
> tricks and blasting through a solution. It’s very much like Bob’s
> <https://groups.yahoo.com/neo/groups/4D_Cubing/conversations/topics/3803>
> and Joel’s
> <https://groups.yahoo.com/neo/groups/4D_Cubing/conversations/messages/3904>
> solutions as well as Marc’s <https://www.youtube.com/watch?v=pKHU5sFaGvY>
> approach.
>
> This makes for a great launching point for questions about which moves
> should be included in a canonical set. Of course any move that results in a
> reachable state can be justified in a solution, but there’s such a spectrum
> from "obviously fine" to "obviously not". Now that we’ve gotten some
> experience with this puzzle and the practicalities of solving it, I feel
> it’s time to see if we can find some sort of natural canonical set, so I’d
> love to hear your thoughts.
>
> Here is the list of moves I know about, loosely ordered as described above:
>
> 1. Simple rotations
> 2. 90 degree twists of outer face
> 3. 180 degree twists of side face
> 4. Center face axial twist
> 5. Arbitrary half-puzzle juxtapositions
> 6. Clamshell move
> 7. Whole-puzzle reorientations
> 8. 90 degree twist of side face (each 2x2x1 square rotate in opposite
> directions)
> 9. Single end cap twist (with parity restrictions?) [fine for
> scrambling]
> 10. Restacking moves [fine for scrambling]
> 11. Single piece flip
> 12. Reassemble entire puzzle
>
> I suspect the trickiest part has to do with #9 which is the one I would
> most like to nail down.
>
> I intend to create a follow-up video to talk about all of these and any
> others you can think of. The way you can help is to offer additions and
> corrections to the above list, and especially in suggesting ways to reorder
> it. Then please suggest where you’d draw three lines:
>
> - Everything above is primitive (Or "basic" or "elementary" as Joel
> calls them)
> - Everything above is canonical. IE always acceptable in solutions
> - Nothing below is acceptable in solutions.
>
> Thanks all!
> -Melinda
>