A Collection of Cubing Curiosities

Discussion in 'General Speedcubing Discussion' started by macky, Aug 23, 2011.

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  1. Robert-Y

    Robert-Y Super Moderator Staff Member

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    I noticed this one on your webpage:

    "An E-perm: (LU'Ru2L'UR')2. This is N-perm with u2 instead of U2."

    If you replace U2 with E2, it becomes a Z perm.
     
  2. TMOY

    TMOY Member

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    And LU'Ru2L'UR' LU'RU2L'U(LE2L')R' is a V-perm.
     
  3. cmhardw

    cmhardw Premium Member

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    Lucas, my apologies. I likely misremembered who had done the analysis (I'm the one who mentioned Michael Gottlieb in my post to Macky). Michael, did you do any analysis on this as well? Apologies if I have not given credit where credit is due, that was not my intention.
     
  4. Kirjava

    Kirjava Colourful

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    LL Scramble; B2 D' F R2 F' D B U2 B U y2

    OLL; R U R' U'

    Feliks found this one.
     
  5. cmhardw

    cmhardw Premium Member

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    I know it's been said already, but Feliks' technique is amazing!
     
  6. DavidWoner

    DavidWoner The Punchmaster

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    Erm, what do you mean he found it? This is an old trick for FM. It also applies to L R F2 R B L' U2 L B' R2 F L' which is oriented with r U' L' as well others I'm sure.
     
  7. macky

    macky Premium Member

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    Added more. Thanks for your contributions.

    ah, I see. Did someone show that the commutators themselves are closed under composition? I remember reading something like this. In that case, I would mention the Sune is a representative non-obvious example.

    I'd be interested in seeing some more.


    Yeah, for things that multiple people have known for a while, I want to replace the "suggested by" with just a nameless link to the source post. On the other hand (not really a reply to your comment), I think "popularized by" should stay; if Feliks really did popularize that one case enough case to turn that trick into common knowledge, then he deserves a mention, like with Rowe's E perm. In any case, speak up if there's any doubt.
     
    Last edited: Aug 25, 2011
  8. qqwref

    qqwref Member

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    I don't remember doing any analysis on this.


    Another curiosity: certain algs can be done on only the top face of a bigger cube simply by replacing some of the moves. For instance, RwURw'U'Rw'FRw2U'Rw'U'RwURw'F'. The canonical Y perm works too, and Fw2UM'U2MUFw2. This is somewhat surprising since many common/fast algs do not do this. The R'U2RU2 R perm doesn't work, or the 2-gen U perm and the RU2R' style J perm doesn't although the RUR'F' one does. The MU H-perm works, the 2-gen one *almost* works (it does the intended effect plus two edge 2-cycles), and the RLU2 one almost works as well if you do it right. I'm still not really sure why some algs work and others don't, but it's definitely curious.

    EDIT: Oh yeah, something else that I think I discovered: any PLL (any ZBLL, actually) can be done completely 2-gen plus exactly one F and one F'. The same thing occurs for D/D', B/B', and L/L'.
     
    Last edited: Aug 25, 2011
  9. Athefre

    Athefre Member

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    Are you including recognition time when you say "faster"? Because surely, when using freecenters, the five move MU'M'UM' (UL/UR at UL and DF) and M'U'M'UM' (UL/UR at UL and UB) can be performed faster than the nine move RrUM. Even M'U2M'UMUM'UM' (UL/UR at UF and UB), which is the longest freecenter six-flip, is pretty fast.

    Including recognition time though, it may be quicker to use your RU'r'U'M'UrUr' instead of searching for UL and UR to save four moves.

    I hate to not add anything to the topic. I tried, but nothing came to mind.
     
  10. Kirjava

    Kirjava Colourful

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    Yeah, I wouldn't rely on that. I only misorient centres when I happen to have recog'd white/yellow during CMLL and know a trick for the case.
     
  11. Lucas Garron

    Lucas Garron Super-Duper Moderator Staff Member

    Hmm, I don't think this ever came up here: G = <UF, RBL> (Rokicki's proof)

    From the same thread: A set of two random cube elements is about 50% likely to generate the entire cube group.
     

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