Ahh, thanks for the alg link; that's what I needed. But wait, d is not d? Apparently the solve given
by the program uses "d" to mean, a single slice turn, but (for instance) alg.cubing.net uses "d" to
mean, an outer block turn of depth two. What good is a notation that's ambiguous?
SiGN is defined here:
http://www.mzrg.com/rubik/nota.shtml
Short version: Use SiGN, and the world will live as one.
Story time:
Back in the day (mid-'00s), r had two meanings: turn the two outermost slices together, or turn the second-outermost slice.
The Japanese also had Rw for "wide" outer turns. But the rest of the world didn't use it, except
Macky. For 3x3x3, the "Western" world basically used r to represent wide turns.
For big cubes, people sometimes used r to mean one thing, sometimes the other thing, and sometimes switched depending on whether their alg had more slice turns or more block turns. Of course, people didn't really specify which notation they were using, so this was all not very good. There is no reason that every time someone writes a 4x4 alg it should be ambiguous.
A few of us on IRC, including me, qqwref, and probably Kirjava, took some of the common conventions and formulated a simple notation we called SiGN.
It was simple because an uppercase letter meant a single slice and a lowercase letter meant multiple slices; adding a number like 3R or 3r would specify which slice/how deep to go. In addition, R simply meant the outer slice, and r was the simplest multi-slice outer block turn (two slices) -- which was consistent with one common conventions.
Apart from allowing 3-5r for non-outer block turns, that's just about it: If you see an R it means a single slice, if you see an r it means multiple slices.
Everything was great because we now had a simple standard that we were going to start using, and encouraging everyone to use. It was easy to learn, consistent, and at least *something* we would hopefully all agree on. Some day, people would forget r had ever had another meaning. (Slight dramatization, but that's basically how I felt.)
Unfortunately, this was exactly the time when the WCA saw a need for an official notation. It was introduced
in 2008. Ron probably saw the notations that were in use and thought that it would be clearest to use Rw for wide turns.
But for some reason still unknown to me, the Regulations also defined r turns... as inner slice turns slice. I don't know the reason for this, because the
links to the official scramble pages never used these turns, and 3x3x3 FMC didn't really need them.
This kind of threw a wrench in the whole thing, because the WCA notation was the closest the community had to a standard. SiGN was fairly common, but (partially because of the WCA notation, I assume) people still used r to mean a single slice when it was convenient -- after all, now everyone was comfortable with the meaning of Rw if you needed some wide turns to go with that.
In the end, I don't *really* care which meaning r takes on, but I was annoyed because this directly contradicted the most important detail of our effort to get everyone speaking the same notation -- all due to a Regulation that defined a turn the WCA didn't even use or need.
When I was writing alg.garron.us, I begrudgingly used Randelshofer's tools to generate a secondary WCA notation specification, but I set SiGN.
I was going to start a small "unofficial" cubing standards body and start getting the community to agree on RFCs for things like this, but the Regulations sort of fell into
disrepair and Tyson brought me on to start the WRC instead. There were a lot of things to do, but I took out those "Inner Slice Moves" before we even reached the
first draft].
I still want to get to the standards body thing some day (the Regulations aren't the place for all these things, and in fact it might actually be better to use an external definition for the notation), but I've been busy with the WRC.
Anyhow, the 2012 Regs finally meant that WCA notation and SiGN don't contradict each other, and we can have a universal notation. That's why alg.cubing.net simply uses SiGN with the addition that Rw is an alias for r (this will be permanent).
But the damage has been done. While most people use SiGN, some people like cmowla will still use old WCA notation. I'm not blaming them, but it makes me sad that as a community we still haven't fully settled on a single notation.
Of course, I can't control what notation people use. But we should have a standard, and SiGN is as good as any. It's simple, and I believe it makes the most sense: r can only stand for one of 2R or Rw, and if we're going to have a standard we need to pick on. I believe the latter is better because I find the following reasons for r = Rw more important than the arguments for r = 2R:
- It makes "lower case = multiple slices, uppercase = single slice" very simple to understand for cubes of all sizes.
- Humans can execute wide turns more easily. I think it's better to use the shorter "r" turn notation for the reconstructions and algs people actually use in practice.
In any case, alg.garron.us will start redirecting to alg.cubing.net in a few months (whenever I take a breath from working on the WRC and fix a few alg.cubing.net details first), and all "old WCA" algs will be translated to SiGN. That is,
r will be redirected to
2R.
(also, I would be really amazed if suddenly an optimal solution for an outer layer scramble would include inner slice turns)
