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2x2x2

Sun, 2009-04-19 16:40 — msemtd

[2x2x2]It's all corners!

I first obtained an East-sheen RD02 double 2x2x2 cube on Sat 23rd Aug 08. This is a tiny keychain of two 2x2x2 cubes that share a corner. I would've preferred a straightforward 2x2x2 but I'll take what comes across my path! A fascinating mechanism - there are only corner cubies! This can be quite confusing when you're only used to a 3x3x3 with its fixed centres. The two cubes sharing a corner made this a bit too fiddly to get serious with so I decided to wait 'til Xmas!

Dec 25th 2008: I received a white EastSheen 2x2x2 from puzl.co.uk as part of my self-directed set of Xmas presents and began my true exploration into this puzzle. The Eastsheen 2x2x2 has huge oversized cubies and is great quality -- it turns well from brand new and is a delight to handle. It suffers from the same annoyance of having pink opposite red instead of orange which can cause problems wih colour recognition. I recommend replacing the stickers with the proper colours from Cubesmith.

A Simple 2x2x2 Method

I'm terrible with algorithms so my 2x2x2 technique is a simplified 3x3x3 layer-by-layer method. With only 2 layers it takes the form of: -

  • solve first layer freestyle - I always use white first and solve on top (bad form, I know!)
  • last layer OLL consisting of one of the possible 7 un-oriented states:-
    • SUNE: R U R' U R U2 R' -- same as my 3x3x3 Sune
    • ANTI-SUNE: R' U' R U' R' U2 R -- same as my 3x3x3 Anti-Sune
    • HEADLIGHTS: (F U R) (U' R' F') -- "headlights" to right - reuses a popular 3x3x3 OLL
    • CHAMELEON: (R U R' U') (R' F R F') -- facing left with "eyes" pointing F & B
    • DIAGONAL CORNERS: F' (R U R' U') R' F R -- same orientation as my 3x3x3 OLL
    • SYMMETRIC CORNERS/"HANDS UP!": R2 U2 R U2 R2 -- funky move when no LL cubies oriented, two pointing away and two pointing towards
    • NON-SYMMETRIC CORNERS/"CARTWHEELER": F (R U R' U') (R U R' U') F' -- no LL cubies oriented, two point left, one away and one towards - reminds me of a figure beginning to cartwheel!
    • I only use a single PLL to swap the cubies on the right - if I'm unlucky I have to do it twice!

 

Ortega 2x2x2 Method

Recently I've been trying to improve my 2x2x2 times by using the Ortega Method. It's not too hard to learn as it is basically the layer-by-layer method with one major shortcut and a few extra algorithms: -

  • solve the first side, any side, as quickly as possible without bothering to build a correct layer
  • with the solved side on the bottom, solve the opposite side with the OLLs (as above)
  • use a single algorithm to permute both layers simultaneously - there are 5 cases (plus the already solved case, and two of which only involve the top layer!)...

 

Starting with week 33, I'm now using the Ortega method in the speedsolving.com weekly competition. I tis clear that I have a lot to learn as my times are similar to my LBL method although I am now colour neutral! A lot has to do with recognition of the PLL cases and I still make mistakes in the OLL stage!

As with a lot of these puzzles, speed comes with experience and recognition: here's some tips that I'm trying to follow myself! :-

  • following completion of the first side it will either be complete, require a diagonal PLL, or require an adjacent PLL. If adjacent PLL is required then both subsequent algorithms for both layers require the pair to swap to be at the back so put it there and remember. any possible  orient it in the bottom layer based on the PLL it requires and remember it. If layer is complete or a diagonal permute then I can't save much doesn't matter

 

 

OK, so being the geek that I am, I've created a nice printable OpenDocument drawing, with PDF and PNG versions: -

Feel free to copy them, change them, whatever you like! I think I got most of these algorithms from Erik's 2x2x2 pages - they seem to be down at the moment as he rebuilds his site: http://www.erikku.110mb.com