# Learning algorithms backwards vs U2

#### jdh3000

##### Member
In cfop 3x3 I know some algorithms right and left. I'm not talking about mirrored algs, but just executing one from the left instead of the right, rather than doing a U2.

I was wondering if anyone felt the need to learn every alg this way, or if doing a U2 was good enough...

Some olls are easy from either side,but others would take a bit of committing to muscle memory to do effectively.

I've just been doing U2 for most but have been pondering learning an opposite.

What are you doing?

#### patricKING

##### Member
In cfop 3x3 I know some algorithms right and left. I'm not talking about mirrored algs, but just executing one from the left instead of the right, rather than doing a U2.

I was wondering if anyone felt the need to learn every alg this way, or if doing a U2 was good enough...

Some olls are easy from either side, but others would take a bit of committing to muscle memory to do effectively.

I've just been doing U2 for most but have been pondering learning an opposite.

What are you doing?
I usually do OLL from only the right side (2 Look), but I can do some F2L cases from both sides, such as sledgehammer.

#### xyzzy

##### Member
Most good RUF algs become mediocre or terrible if you try to execute them unmodified from the U2 angle, since they're now LUB. If you're ambidextrous enough, RU→LU, RUD→LUD, RUL→LUR, RUS→LUS might be reasonable. And of course MU algs remain as MU, just with all the Ms switched with M's and vice versa.

I don't think I use any y2'd algs other than the A perms (y2 x R' U R' D2 R U' R' D2 R2 x' y2 = r' U r' B2 r U' r' B2 r2). For the alg combos involving Sunes, I might do one of the Sunes lefty to avoid a U2 AUF (e.g. R U R' U R U2 R' L' U' L U' L' U2 L), although I very rarely do standalone Sunes lefty.

#### Cubing Forever

##### Member
Most good RUF algs become mediocre or terrible if you try to execute them unmodified from the U2 angle, since they're now LUB.
I'd like to mention a few exceptions:

T perm becomes LUF
N perms remain RUF
V perm is pretty much the same except the first 4 moves are L' U L' U' instead of R' U R' U' and you do y' instead of y.
F perm becomes LUF

There are many more but I'm lazy.

#### abunickabhi

##### Member
I think it boils down to personal preference. Sometimes depending on the hand grip, doing a U2 is effortless, or if we have drilled the backward alg, we may pull it off.

It is all depending on the hand grip, and also personal perference. Tough to give an objective answer for such choices in alg execution.

#### Cubing Forever

##### Member
I wasn't talking about mirroring, and neither was jdh3000.
Well, I wasn't either. I was giving a few exceptions for "most RUF algs become mediocre or terrible if executed unmodified from the U2 angle since they become LUB".
Also, mirroring the alg is somewhat similar to executing it from the U2 angle.

#### xyzzy

##### Member
Well, I wasn't either. I was giving a few exceptions for "most RUF algs become mediocre or terrible if executed unmodified from the U2 angle since they become LUB".
Also, mirroring the alg is somewhat similar to executing it from the U2 angle.
The only one you listed that sorta counts is the V perm, and it's not even an RUF alg to begin with.

When you execute R U R' U' R' F R2 U' R' U' R U R' F' from the U2 angle, it becomes
L U L' U' L' B L2 U' L' U' L U L' B',
not
L' U' L U L F' L2 U L U L' U' L F.

These happen to solve the same case (because it has reflection symmetry), but they're obviously not the same alg. The first one you get by rotating the original alg, the second one you get by mirroring the original alg. The first alg is bad and no one should use it. The second one is good if you're ambidextrous.

AIUI, the point of this thread was to ask about algs that are transformed by rotating 180°, not to find algs specifically optimised to be executed from that angle that are possibly unrelated to the alg for the "standard" angle, or related in ways other than 180° rotation. Of course when you relax the constraints on the algs you choose, you can find better algs.