One-Answer 4x4 Question Thread

[BenChristman1]

Yes, this is called PLL parity. The standard alg for it is 2R2 U2 2R2 Uw2 2R2 Uw2, which you can also view here.

Also, just for future reference, you should post questions like this in a megathread, such as this one that’s specifically for 4x4.

 

[qwr]

local cuber discovers 4x4 parity

 

[Filipe Teixeira]

local cuber discovers 4x4 parity

lol welcome to 1981

jokes aside congrats on solving until that case

 

[tano12345]

This is my cube. The sides that are not visible are solved properly (all white / all green).
Is it possible to solve it at all?
The cube got broken up accidentally and I'm unsure I assembled it correctly (its a long time ago).
I (believe I) can solve it via reduction and regular 3x3 algs. Is there a way to get the reduction wrong?
Thanks and please apologize if I violated some netiquette. First post here.

 

[Christopher Mowla]

This is my cube. The sides that are not visible are solved properly (all white / all green).
Is it possible to solve it at all?

Anyone of the first 8 algs in this list will solve it completely. (Just apply the algorithm with blue in front and yellow on top.)

 

[Platform]

Qual è il nome della persona che ha creato il metodo di speedsolving 4x4 utilizzato dai risolutori più veloci del mondo?

 

[qwr]

Anyone of the first 8 algs in this list will solve it completely. (Just apply the algorithm with blue in front and yellow on top.)

If you are going to include algorithm authors (which I support), you might as well go all the way and include date of discovery and links to original publications

 

[Timona]

Qual è il nome della persona che ha creato il metodo di speedsolving 4x4 utilizzato dai risolutori più veloci del mondo?

Robert Yau

 

[Christopher Mowla]

If you are going to include algorithm authors (which I support), you might as well go all the way and include date of discovery and links to original publications

I already did to the best of my ability.

Many, but not all, algorithms have this already. If they did not, they most likely came from a Cube Explorer search, for which it would be unknown who originally found it. Unless an algorithm, such as the 15 move single dedge flip by Frédérick Badie or Lucas Garron's lucasparity, was given specific credit for it, I did not credit anyone for it. I did not take credit for any of the algorithms I personally found in the <U2,D2,F2,B2,l,r> moveset with Cube Explorer (which are the majority of the unmarked algs) because of this.

In that link to the wiki, the algorithm with a [230] goes to the original source of the algorithm. And many of the special PLL cases are from yahoo groups, which was taken down a few years ago. But before they were, I backed up all such pages on to web.archive to preserve that history. (For example, an easy way to see these saved web-pages is to go see any of the links in the the PLL Parity algorithms sub-section of the External links sections.)

Also, I explained this in the second yellow block under this section in the Introduction.

EDIT:
It looks like [230] goes nowhere now, since Ben seem to recently delete (or move) his site. But the majority of the other links shouldn't be broken. (I know of one other one which is broken, as that went to another website other than speedsolving or twistypuzzles, but the majority of all links are to those two forums.)

Robert Yau

That's debatable. (But if you want to debate, please use that thread, not this one. Thanks.)

 

[cubingnobody]

So of course I know this is impossible but for some reason I've been trying to reduce my 4x4 to a 2x2. I've been trying since last night and now I'm on the last piece, the green-orange-yellow piece and the pieces are in a state where twisting the corner anticlockwise would be easier than moving and flipping the surrounding wing pieces. So in conclusion, I'm in need of an algorithm that twists a single corner and moves around only center pieces it touches and no other pieces (if it were okay to twist another corner I'd either use the beginner method technique or that algorithm with a lot of L and D moves). I hope something like this exists

 

[xyzzy]

It's not possible to twist a single corner by itself. You really just have to move the three wing pieces around it instead.

(It's very much possible to do 4→2 reduction, just usually not recommended because it's much harder than the alternatives.)

 

[cubingnobody]

It's not possible to twist a single corner by itself. You really just have to move the three wing pieces around it instead.

(It's very much possible to do 4→2 reduction, just usually not recommended because it's much harder than the alternatives.)

Thanks, but I'll just wait another day to see if anyone has an algorithm. The reason I think this may be possible is because I'm okay with a couple center pieces moving around.

 

[xyzzy]

No, it's just impossible. Doesn't matter whether you allow moving centre pieces around or not.

(What would be possible is twisting a single corner, while also twisting a 2×2×2 corner block in the opposite direction. But the alg for doing this amounts to twisting two corners, then moving the edge pieces around one of them—which is basically what you wanted to avoid doing.)

 

[cubingnobody]

Thanks so much! By the way, I FINALLY just finished solving my 4x4 after 2 days of pain lmao

 

[abunickabhi]

Thanks so much! By the way, I FINALLY just finished solving my 4x4 after 2 days of pain lmao

Nice, congrats on solving the 4x4.

Now onto the 5x5 puzzle.

 

[Garf]

Nice, congrats on solving the 4x4.

Now onto the 5x5 puzzle.

Abijeet, he was reducing a 4x4 into a 2x2, There is no other possible for 5x5 other than to a weird 3x3.

 

[cubingnobody]

Nice, congrats on solving the 4x4.

Now onto the 5x5 puzzle.

That reminds me of when I solved my 5x5 layer by layer with more commutators than ever

 

[hurrythedivinephysician]

I keep getting this case on 4x4 and no parity algs or regular algs are solving it. Every other side is solved except for these two.

 

[xyzzy]

I keep getting this case on 4x4 and no parity algs or regular algs are solving it. Every other side is solved except for these two.

If you're trying to use the reduction method, you didn't finish the edge pairing step. (The unsolved edge pieces in your picture are yet to be paired.)

 

[Filipe Teixeira]

can you give me tips? (the video is long, it's ok if you just pass your eyes on it)