# 3x3 picture cube - centre piece rotation

#### hawk43

##### Member
Hey guys I'm brand new to speed cubing, I have something that keeps bugging me on a picture cube and hoping someone can help me. The problem is that sometimes when I finish, my top centre piece is rotated 90 degrees but all other centre pieces are correct.

I know how to fix one centre piece but that then causes another one to be off. So basically I have 2 questions:

1. Is it possible to rotate the one wrong piece without affecting any others? (I dont think it is).

2. If no to the first question, is there something I can do earlier to avoid the rotation at the finish? There must be seeing as sometimes it works out fine.

This has really been bugging me and really slowing down my times so any help is really appreciated.

Thank you!
Jess

#### AlexCube

##### Member
If you have to turn one center piece twice, alg is: R2 L2 F B' U2 F' B R2 y' z2 M' U2 M U2. I figured that out myself. It's easier when you understand how it works If you don't know the notation (x, y, z), check this out: http://badmephisto.com/notation.html Hope this helps

#### TDM

##### Member
If it's only one centre and it's 90 degrees from being solved, you can't solve it, no matter what you do earlier in the solve. Disassemble your cube and reassemble it completely solved. Then you'll be able to solve it. If you need to turn a centre 180 degrees, use (R U R' U)*5

##### Member
If you have to turn one center piece twice, alg is: R2 L2 F B' U2 F' B R2 y' z2 M' U2 M U2. I figured that out myself. It's easier when you understand how it works If you don't know the notation (x, y, z), check this out: http://badmephisto.com/notation.html Hope this helps
Or just do T-perm twice
Or just (R U R' U)5

#### AlexCube

##### Member
Or just do T-perm twice
Or just (R U R' U)5
Well ok nice. I didn't know about those

#### hawk43

##### Member
This doesn't make sense tho because it was assembled correctly in the first instance and this keeps happening. Sometimes I complete it using the normal algorithms and it works fine yet sometimes I do the same thing and the top centre piece is rotated 90 degrees, so there's obviously something I'm doing early, has me completely stumped

#### TDM

##### Member
This doesn't make sense tho because it was assembled correctly in the first instance and this keeps happening. Sometimes I complete it using the normal algorithms and it works fine yet sometimes I do the same thing and the top centre piece is rotated 90 degrees, so there's obviously something I'm doing early, has me completely stumped
That's impossible. Either you have 1 centre 90 degrees out, or it's solvable. You can't solve it if one centre is a 90 degree turn from being solved. If you ever have just one side with a 90 degree turn to do, take the pieces off that side, correct the centre's orientation, and put the pieces back in.

#### hawk43

##### Member
Ok I just did that and the same thing happened again, maybe my cube is cursed...

#### IQubic

##### Member
Okay, check if you have you have a second center out, if so put them, the centers you want to switch, on the top and left faces. Perform this alg:
(R U R' U R U2 R') Y (L' U' L U' L' U2 L') Y' (R U' R U R U R U' R' U' R2)

#### hawk43

##### Member
There's def not another centre piece out. Honestly I'll solve it and everything is fine and is completely solved then I'll do it again and the top centre piece is out. It's bizarre but I do really appreciate the help

##### Member
Is there one side which is plain, or has rotational symmetry for 90 degrees? if so, that side is also "wrong". You need to rotate that centre by 90 degrees as well.

#### Renslay

##### Member
There is a mathematical proof that turning only one center with 90 degrees is impossible. The sum of the center turns must be divisible with 180.

If you have to turn one center with 90 degrees, then you have to turn another center with 90 degrees as well.
Like Aceofspades2345 said, maybe there is a center piece which seems solved no matter how much it is turned. Then turn these two center pieces with 90 degrees.

For example an algorihm for turning U center with 90 degrees CW and L center with 90 degrees CCW:
U M E M' U' M E' M'

#### cuBerBruce

##### Member
You haven't described your cube other than that it's a picture cube. Is it a "proper" picture cube with only one solved state? If you have two edge pieces that look the same and two corners that look the same, it's possible you're swapping these two edges and these two corners. This could result in one center only appearing to be rotated 90 degrees and all other centers correct, while everything else looks solved.

#### cuBerBruce

##### Member
Maybe one of the other center pieces can be rotated also and still be correct?

#### hawk43

##### Member
You haven't described your cube other than that it's a picture cube. Is it a "proper" picture cube with only one solved state? If you have two edge pieces that look the same and two corners that look the same, it's possible you're swapping these two edges and these two corners. This could result in one center only appearing to be rotated 90 degrees and all other centers correct, while everything else looks solved.
Okay thanks it looks like this was the issue there's actually 2 edge pieces which looked exactly the same and fixing that seems to have fixed the issue. Great pickup thanks again

#### Enderger

##### Member
T-perm and solving via beginner’s PLL rotates the top once and the back twice

#### Enderger

##### Member
Provided that the method used Z-perm