# Message #4071

From: Marc Ringuette <ringuette@solarmirror.com>

Subject: Re: [MC4D] 2x2x2x2: Monoflip demo side-by-side with MC4D

Date: Thu, 19 Jul 2018 13:22:23 -0700

Andy,

Oh, now I see what you were saying about the Iy macro’s algorithm

looking RKT-ish. I think you confused me (and perhaps yourself) by

including the final IU move in the RKT portion. That final move messes

up the "0 mod 4" and leaves a twist in the buffer piece. Instead, I’d

consider the final IU move separately:

Iy (phys) = *IU’ RO2 IF RO2* *IU **RO2 IF’ RO2***IU**(virt)

The bold part above corresponds precisely to a nice 3D algorithm on the

*I *subcube, *F2 U2 R2 F2 z’ y’, *that does not permute any pieces at

all, but reorients all of them. This is exactly what is needed, since

the final *IU *is very like the desired *Iy*, permuting the pieces the

same, except that all the orientations need to end up differently.

Cool.

Cheers

Marc

On 7/19/2018 10:19 AM, Andy F legomany3448@gmail.com [4D_Cubing] wrote:

>

> The *Iy* macro looks like RKT-ified F2 U2 R2 F2 U2 y2 z(equivalent to

> (F B) R2 U2 B2 R2), which is a very bizarre algorithm.