I’ve discovered something kind of interesting. To me, anyway. 
You see, I’d decided I wanted a hat to go with my Fetching wristwarmers. This meant applying the stitch pattern and cables used on Fetching to a hat. Well, with a couple of small variations – aren’t there always? What I’ve discovered is, I approach knitting designing in the exact same two ways I have of approaching music composition.
Usually when I make a hat (or scarf or bag or whatever), I almost completely improvise. Often, I don’t even swatch, I just rely on the fact that I know that I’ll get this approximate gauge with those needles and that weight yarn, and base my number of cast on stitches on that. I’ll keep to approximate guidelines – just like staying within a key (or its relatives) – but otherwise I’ll wing it from there… sometimes even in terms of stitch pattern, although not always. If it works out well, I might go back and record what I’ve done on paper later on.
This time, I used what is actually my other method of writing music: I take a motif that I’ve worked out on an instrument beforehand, then decide on a key, key sig, and orchestration, and write everything else straight down onto paper out of my head. I’m pretty sure I know how it’s going to sound, but there’s sometimes the odd surprise *g*. Along very much the same lines, I started the design for my “Tête à Fetching” hat by taking the motif of the Fetching wristwarmers cables / ribbing which I have already knitted and therefore am familiar with the look of it. I swatched, I calculated, and I wrote out the provisional pattern on paper, including variations which didn’t occur in the original motif. Now, I’m knitting it:
I’ll let you know how it goes, and with luck put the finished pattern up when I’m done!