neat F2L trick

[cmhardw]

Hey everyone,

I ran into this case today, and I've run into it before, and I finally decided to ACube it.

From a correctly oriented LL (with cross on bottom) do: R U F U R U' R' U F' R' F U' F'

This is the particular case, to solve use the inverse of the above or:
F U F' R F U' R U R' U' F' U' R'

By the way, on the 4th slot, the probability of this case is 1/8100 so it doesn't occur often. But when it does you can skip OLL.

I apologize if this has been posted before, but I thought it was neat.

Chris

 

[DAE_JA_VOO]

I would do it differently. Looking at that case, i generally do something long the lines of:

with F2L pair in FR slot:

R U' R' U y' R' U2 R U2 R' U R


I do the cube rotation because i prefer that over F turns, but you could do that same alg like this:

R U' R' U F' U2 F U2 F' U F

But i find that far more difficult to perform.

A quick breakdown of the first alg:

R U' R' - Take the pair out of the F2L slot and pull it apart

U y' - Turn move the corner above a used F2L slot and make way to open the empty F2L slot

R' U2 R - match up the edge and corner

U2 R' U R - insert the now matched pair into the F2L slot.

 

[Lt-UnReaL]

DAE_JA_VOO: cmhardw's alg is for an OLL skip if the whole LL is oriented, though...

 

[Mike Hughey]

Interesting, Chris. I just happened to have only a 4x4x4 nearby to try it on instead of a 3x3x3. On the 4x4x4, it does OLL parity at the same time as solving that slot (with the flipped dedge at UF). And leaves the rest of the LL orientation alone!

 

[Lucas Garron]

Hmm...
I'd probably use z U'R'UR2U2r'R'U'RUrU2' z' (move-cancellation on a 2-flip alg).
MGLS doesn't really get this, though...

I should learn the 3-flip ZB's, though...

EDIT:
Lemme contribute a beautiful alg to the only nasty 2-gen case: R U2' R U' R U R' U2 R'.

 

[cmhardw]

oh my...

R U' L R' F L' U' R U' L R' F L'
Do the inverse of this alg from an already oriented LL to setup the case

This other case (with 4 flipped edges) is so much nicer.

The two cases together have a combined probability of 1/4050 which is still miniscule, but when it happens it's a fast OLL skip.

Lucas, is that alg meant to be a ZBF2L? Or is it an MGLS case? My knowledge of MGLS is rudimentary at best. Either way it's a nice alg ;-)

--edit--
I think this alg is even better for the first case:
r R U R' U' r' U2 R U R U' R2
--edit--

--edit 2--
Oh my God these algs are so fast! I'm going to use them both for ZBF2L purposes (or partial edge control, whatever you want to call it). Dang!
--edit 2--

Chris

 

[qqwref]

I really like that second alg for the first case. As for the second case I think the alg might be a big clearer like this:
(R U' R') (r U r') U' (R U' R') (r U r')

 

[cmhardw]

wow, it gets better:
1) r R U R' U' r' U2 R U R U' R2 U2
is a supercube safe way to flip 2 edges

2) Jason Baum suggested to use the following for the second case:
R U' M' U r' U' R U' M' U r'

----

wow (R U' R') (r U r') U' (R U' R') (r U r') feels very fast too.

will have to try both and see which I can get faster times with.

Chris

 

[Lucas Garron]

wow, it gets better:
1) r R U R' U' r' U2 R U R U' R2 U2
is a supercube safe way to flip 2 edges

Hah, that's a mirror, inverse, rotation, and move-cancellation of my 2-flip (the alg I used above):
RU'R'UR2U2r'R'U'RUrU2'R2

(Actually, I now think I might've done R2U'R'UR2U2r'R'U'RUrU2'R)
I actually setup on R, do the alg, and adjust the final R2 accordingly (invert a single turn, switch parity of doing a half-turn)...

You reminded me to try more variations of my alg to see if I like them more (and maybe find something for UL).

2) Jason Baum suggested to use the following for the second case:
R U' M' U r' U' R U' M' U r'

I have this funny feeling that it's based on something related to the RUM'U'r', but I really can't explicate the conjugate right now...


EDIT: By the way, the alg above was for 2-gen solving. Good for Petrus, restricted puzzles, 2-gen/3-gen challenges, etc.

 

[Johannes91]

Lemme contribute a beautiful alg to the only nasty 2-gen case: R U2' R U' R U R' U2 R'.

Lars has that on his site, so it isn't really new. I prefer the optimal 7-mover, though.