Magic Rules
why,uegs'r
Whirl is designed around two main concepts: Magic and Inroll.
Inroll is an inward roll, for example df on Qwerty. Most people believe that compared to an outroll, it feels only marginally better, if at all. However for me they feel a lot nicer, so I want a layout that maximises these.
There are other people who have the same philosophy, and have created layouts like Mir and Rain. However, inroll layouts tend to have a lot of drawbacks. For example, Mir has a very, very heavy pinky, as it has e on pinky which is around 12%, and relatively high SFB and SFS (0.9% and 5.9% respectively), and Rain has bad scissors and SFS (5.3%). There is a layout called Wreathy, which as far as I know no one has ever used, but it is an inroll layout with neither scissor nor pinky issues. The SFS and SFB though aren't much better than Mir's, and the Inroll isn't nearly as high.
Whirl, altohugh not meant to be a mod of Wreath, accidentally became quite similar to Wreath, but fixes the SFB and SFS issues with it, so essentially becomes the "perfect" inroll layout, but there is a catch:
Magic is a bit of a vague concept that refers to using a key that has a different output depending on the key pressed before. This has varying complexity, with some people using a concept called Word Builder, that almost becomes Steno-like in its difficulty curve, but theoretically is very fast and comfortable. I agree with the majority of people that complex magic is overkill and way too hard to learn, but I think that with simpler magic you can have muscle memory on-par with that of a traditional layout. My principle is to only magic bigrams, so I can fix SFBs and theoretically any scissors, though Whirl does well in that regard so its not necessary. I also try and minimise the amount of magic rules, to make learning as easy as possible. I take advantage of the magic key to introduce a wh index column, which usually would be completely unviable, but I simply magic the SFB and it is good. Wreathy puts the w key onto the right index, which introduces the SFBs wr and wl, as well as SFS, making Wreath a pretty mid layout. I use the ability to essentially ignore the SFB stat to my advantage, and instead use columns that have very low SFS. However nothing can be that easy so I have a completely optional self-imposed limit:
A repeat key is essentially magic, but much simpler in that it just repeats the output of the last akey pressed. This means you don't have to press your finger twice fast, which is a theoretical big limiter of speed, as you can press two keys as fast as you like, but there is a finite speed that you can reach on a single key. Generally the best place for a repeat key is thumb, but that is also the place I have the magic key! This is where my abomination comes in.
After a letter like l which often repeats (think all), my thumb key acts as repeat. However, after letters like w which almost never repeats aww, the key acts as magic. This is why I specifically have the wh column, rather than something with a repeating letter. That key also acts as shift after either a timeout or after pressing space, but that's not relevant to the design of this layout.
Obviously no layout is perfect, though Whirl is pretty close (:
The SFB becomes pretty low with my magic implementation, around 0.57%. However there are still some major SFBs because I don't magic repeat letters, such as rl, sc and pt. If you magic these the SFB becomes around 0.3%, so this is a non-issue if you're not stubborn to use a repeat key like I am.
There is only one scissor that annoys me on this layout: b_g, for example begin. This is whats known as a Full Skip Scissor, or FSS, but luckily its not especially common (0.06%). There are however a few Half Scissor Bigrams, or HSBs, that don't annoy me but may annoy other people, such as nc and al. Many of the scissors can be fixed by moving l to the bottom row, but having it on top row creates same row rolls and I don't feel the half scissors anyway.
While I personally don't mind it, the right pinky has a yi, column, which has a lot of movement and usage for a pinky, but leads to good stats. For many people this is a deal breaker, but I personally don't mind it. You can swap ', to reduce this which adds the easily-magickable SFB I', but also r, and l,.
The right index only really has two letters, r and l, which along with rn is one of the two real options for the vowel index to get good inroll. Annoyingly both of these columns really can't support other letters, rn can have b, rl can kinda have w (like Wreathy), so the index ends up having almost nothing, which isn't inherently bad but it leads to other fingers being pretty heavy.
All these issues are pretty minor and for me Whirl is still the best option.