And, well, what shall I say? I was mostly successful, and I can now give you this:
Woven on a 42 tablet wide band, with no pattern drawing. Not even a sketch.
Actually, I did make several sketches, but in the end, I followed none of them. I was sitting there, weaving, and that certain part of my brain went "I think I should do this here" or "wonder if I can't give that horse a mane" or "this doesn't look wide enough yet".
Obviously, it did not go all smoothly all the time - I did botch up at a few different occasions, once so badly I actually had to un-weave two picks. The tablets were a bit out of sync after one point (damn you, directional change at odd weft counts!) and that did make going on, and matching lines together, a lot harder than it should have been. So in the end, I had some parts that were running smoothly and some wonky places between them where I sort of just fudged it. The smooth parts were partly in sync and partly not, so the wonkyness went both ways, and it was rather a relief to find that the head blob had finally gotten long enough, as had the front legs, so that I could just turn everything pink again and call it a day. Or a horse.
However, being able to go on and actually finish the critter proves, to me, that the system does work very well - because the last times I got out of sync in a similar way, or even less direly, everything got so confusing that I basically gave up and restarted with a clean slate. This time, it was possible to muddle my way through, and the next critter will surely be less wonky again. I've also realised that there are some more hints (that can probably be turned into rules) to prevent things like this from happening again.
So. Achievement unlocked: Twill patterns without pattern.
And what kind of critter will I weave now?