I am surprised that no one has not said anything, but if someone
really wants to
avoid parity algorithms AND parity fixes (which are more than 1 move
to fully resolve the parity), they need to determine whether the permutation of the
24 wing edges is odd or even before the third composite center is completed. This is definitely okay if they are
not worried about speed, but cycle counting is a sure way to avoid OLL parity -- when starting with a fully scrambled 4x4x4.
I guess no one said anything because that's not what Magmatic's post is about -- just
detecting parity. Fair enough. But still surprised.
Five things:
- If someone doesn't like to learn one (parity) algorithm, why would they choose to learn an entirely new (well, your method is like Sandwich, which is more than a decade old -- or Cage, which is about two or maybe even three decades old) method which requires many algorithms? (See footnote 1.)
Especially if they knew the full truth behind it (and its false promises). The worst part of Sandwich, cage, etc., is sometimes it happens that a 2-cycle of wings will appear in the last slice unintentionally. So you have to fix the parity anyway. (It's not a fool-proof avoidance approach. It just increases your chances of not getting it. But you will have to constantly "fight it off" during the solve like a fly buzzing in your ear.)
- I think Magmatic's chosen way to detect if OLL parity exists is most "cost effective" for beginners. (Of course, this concept is rudimentary to some of us, but it was new to him and he wanted to share. So that's a nice gesture.)
The only premise for "Magmatic's approach" is that someone is solving the 4x4x4 with Reduction (or one of its variants) and that they need to learn what a "good edge" and a "bad edge" is. (Which is obviously a rather useful skill for Petrus, Heise, etc.) It doesn't require them to learn a method which is overkill just for the sake of avoiding parity algorithms -- a method which does not guarantee that at all as stated in bullet point #1.)
- Your method doesn't help to "understand parity as a concept" any more than doing an inner slice quarter turn and then see what happens. As a matter of fact, all you are doing is solving a cube until it becomes in the same state as if someone did a slice quarter turn to a cube. So you would rather spend at least 50 moves more, make the solving process harder three fold, just to arrive at the same state that you could get from the end of reduction (that is, if you just simply choose to fix the parity by doing an inner layer slice quarter turn)?
- Some people have solved the 4x4x4 rather quickly with Cage, Sandwich, etc. (Essentially with your chosen method.) So it most certainly can be a speed method. It may not be a WR method, but solving the 4x4x4 in around a minute with it isn't unheard of.
- How did my video (that I linked to previously in this thread) not help understand fixing parity (without wrecking the cube) intuitively? Just curious.
(Again, I might be a little biased, but in that video I explicitly stated that "You can use any moves you wish, as long as you write down the moves you use" to make a certain pattern of centers in a 4x4x4 inner layer slice.)
As a simile, the "method" in my video is to fixing parity as laser surgery can help remove an obstruction with precision and "as little mess" as possible. Your chosen approach is to fixing parity as shuffling someone's insides until you feel the obstruction . . . where when you "feel it", you may keep moving it around before you actually get it out.
My video may be 17 minutes long, but I repeated myself quite a bit.
Footnotes:
- Yes, I love commutators and I can say I know my fair share about them. But they ARE algorithms. They don't come natural, but with memorization based on successful results from experimentation.
timkoop.com
