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5x5 Picture Cube Last Center Help

prc11482

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Apr 8, 2021
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I apologize if this isn't the correct place for this question but this is driving me nuts. I'm working on a 5x5 picture cube that I was given as a present. I have all the center 3x3 pieces solved and orientated correct, with the exception of the last one. The center piece needs to be rotated 90 degrees, and UR and UL need to be swapped, but I can't for the life of me figure out how to do this, and can't find any algorithms online. If anyone has any suggestions or advice, I'd greatly appreciate it, photo attached for reference, thanks.
 

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Scollier

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I apologize if this isn't the correct place for this question but this is driving me nuts. I'm working on a 5x5 picture cube that I was given as a present. I have all the center 3x3 pieces solved and orientated correct, with the exception of the last one. The center piece needs to be rotated 90 degrees, and UR and UL need to be swapped, but I can't for the life of me figure out how to do this, and can't find any algorithms online. If anyone has any suggestions or advice, I'd greatly appreciate it, photo attached for reference, thanks.

For swapping the UR and the UL, try watching from 3:00 of this video:

I'm not sure, however, if when you swap them, it will orient them correctly.
 

xyzzy

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Dec 24, 2015
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I apologize if this isn't the correct place for this question but this is driving me nuts. I'm working on a 5x5 picture cube that I was given as a present. I have all the center 3x3 pieces solved and orientated correct, with the exception of the last one. The center piece needs to be rotated 90 degrees, and UR and UL need to be swapped, but I can't for the life of me figure out how to do this, and can't find any algorithms online. If anyone has any suggestions or advice, I'd greatly appreciate it, photo attached for reference, thanks.
This probably works:
2R U2 2R U2 2R U2 2R U2 2R // swap Ul-Ur, Uf-Ub, Urf-Ulb, Ubr-Ufl
y'
r U r' U' r' F r2 U' r' U' r U r' F' // wide T perm; swap Urf-Ubr, Ul-Ur, and also rotate U centre


(Hold the cube in the same orientation as your picture, with the shown face being the top face.)

You should be trying to solve the corner-centre and edge-centre pieces around the "central-centre" pieces (man, do we have a better name for this?), rather than swapping them around after the fact.

The parity of the corner-centre pieces is always the same as the parity of the total centre orientation; as a sanity check, here you have a 2-cycle of the corner-centres and the central-centre is also an odd number of turns off. You can fix this by solving the corner-centre pieces around the central-centre, for instance by using the wide T perm alg I wrote out above or by doing a 3-cycle commutator.

The parity of the edge-centre pieces, on the other hand, are independent of the other centre piece types, and are only affected by turns of the inner slices. The usual methods of solving the third through fifth centres (and also doing edge pairing) basically consist of basic algs of the form Rw [some outer layer turns] Rw', and so can never affect the parity; you need to break up the other centres and restore them in a way that uses an odd number of quarter turns of the inner slices in total. This is exactly what 2R U2 2R U2 2R U2 2R U2 2R in my example does (five quarter turns of inner slices, an odd number).

I just peel the stickers of... you could try that... or you could pop the center cap off
Unfortunately, these are both bad suggestions. Peeling off the stickers is an obviously bad suggestion – have you ever tried peeling off stickers and putting them back on? It never ends well. Turning the centre cap by itself is a nonobviously bad suggestion because it leaves the cube in an unsolvable state.

All the moves on the cube are reversible; if you didn't "cheat" while scrambling it, then in principle, you will never need to resort to cheating to solve it: just do all of the moves in reverse.

I'm not sure, however, if when you swap them, it will orient them correctly.
The video's method involves 3-cycle commutators (sort of). You cannot swap two things with 3-cycles. (Not because 3-cycles move three things (which does not, by itself, preclude the possibility of using multiple 3-cycles with the resulting effect being a 2-cycle), but because of parity.)
 
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