Trouble with PLL cases #1 and #2

[Kolraz]

Hiya everyone.

I thought it was time i began to learn plls to start a 3 look last layer. I have decided to use cubewhiz (run by bob burton). I am having trouble with what he says on how to distinguish between cases 1 and 2.

"In cases #01 and #02, I first AUF (adjust the U-face) until the "corner block" is permuted. By corner block, I mean that there is a corner and the two edges adjacent to it belong adjacent to it. Since this is very similar to case #18, i check to see that the two stickers next to the corner block are the same color (if they are not, then this is case #18). To distinguish between the two cases, I look at both sides of the corner block. I rotate the cube so that whichever of those sides shows the sticker of a corner that belongs opposite along the diagonal of where it is located. I use that as an indicator for which algorithm to use. For example, if there is a solved blue-red corner block, and the rightmost sticker on the red side is orange, then I know I have Case #01. Case #03 is obvious to recognize because there are no 1x1x2 (or larger) blocks. Thus, I just AUF to permute any edge (the other three will be permuted by default), and rotate the cube to match the diagram below."

Has anyone got an easier way to explain this because i just dont understand how i can recognise the cases quickly with this explanation.

 

[McWizzle94]

first permute the corner block, so that the colors match up with the sides. then look at the back-right-up corner. If it matches the colors below it, then it is case 18. if not, then all of the edges will be permuted correctly, and you will have case 1 or 2. then just find out which direction they go, and do the algorithm. finding out the direction will come easier with practice. i hope this helped.

 

[pcwiz]

It means..

Adjust the U-face until you have a permuted corner piece on the lower left hand side of the U face. Then, do one of the algorithms (case 1 or 2) to permute the corners in a clockwise or counterclockwise cycle. If you don't have one corner permuted (there will be two and they will be across from one another), adjust the U-face until you have one permuted.

If you have two corners already permuted in a diagonal direction, do case 18 (I just learned that algorithms today) The first permuted corner piece should be on the bottom left hand corner of the U face and the other one on the top right hand corner of the U face. That algorithm will permute the corners, and it may permuted the edges.

Cases 1 and 2 only permute the corners, and case 18 will permute the corner and might permute the edges (depends on the position of the cube.)

Case 1 (clockwise cycle) - (l' U R') D2 (R U' R') D2 R2
Case 2 (counter-clockwise cycle) - x R2 D2 (R U R') D2 (R U' R)
Case 18 - (R' U R' d') x (l' U R' U') (l R U') (R' U R U)

 

[Kolraz]

OK the problem was with the description of how to recognise which direction. I know i could just look but that would take a lot longer. Im sure it is trying to describe a faster way of recognising it but i don't understand it.

Also, Presumably if i do case 1 follow by case 2 i am left with a solved cube, however this is not the case.

 

[pcwiz]

OK the problem was with the description of how to recognise which direction. I know i could just look but that would take a lot longer. Im sure it is trying to describe a faster way of recognising it but i don't understand it.

Okay I'm sort of confused on what you're trying to ask, but I'll try to answer what I understand.

So is your question is how to recognize which direction the permutations go really FAST?

Well if that is the question, here's how I do it (I'm no master at cubing). I look at the front face of my cube. Say for example, it's red. Then my left face is blue. So if the corner piece on the lower right hand side of the U face is orange blue, then I know I have to do the permutation algorithm going in a clockwise cycle. Because that corner piece will go to the top left hand side of the U face. I know blue is my left face and orange is opposite red so orange is in the back. Vise versa for the counter-clockwise permutation cycle. I hope that's not too confusing and I hope I answered your question correctly.

Also, Presumably if i do case 1 follow by case 2 i am left with a solved cube, however this is not the case.

What does that mean?:confused::confused::confused:

 

[Kolraz]

Thanks, your advice was helpful.

What i meant was that if i begin with a solved cube then I do l' U R' D2 R U' R' D2 R2 (clockwise/case 1) then i follow it by case 2/anti clockwise which is x R2 D2 R U R' D2 R U' R then i would have thought it would leave me with a solved cube again but this i not the case.
However, if i follow case with with case 2 without the x rotation in the beginning, i do have asolved cube.

Why is it that i must leave off the x ?

Also, If i do case 1 it presumably leaves me with a cube that needs a case 2 pll to solve it, but if i rotate the cube so the the corner block is permutated in the bottom right (as required for case 2) and perform the algorithm, the pll does not work.

EDIT - Okay after playing around i have realised that it is cubewhiz that was confusing me. For anyone else having a similar problem when learning these algorithms, remember that no matter how cubewhiz have displayed the cube, the correct corner block ALWAYS goes in the bottom left, with both cases. (on cubewhiz it shows case 2 with corner block in bottom right, which does not work)

 

[pcwiz]

Oh okay yeah that's weird Cubewhiz puts it into the wrong position... I've actually never noticed that but I use that algorithm. Well it's the same algorithm as Cubestation so I used it there but I have a printable sheet of Cubewhiz algorithms and I've never notice that!! (Now I do)

Well now you get it so that's a good thing! I didn't really think anyone would understand my explanation before but that's great that you understand it! Thanks!