These were all done using a historical fashion book for reference and a differential calculus book as a canvas.
I first looked for interesting mathematical lines and diagrams, then found fashions that seemed to meld with them. The rest was a bit of swift improvisation. The women in the fashion book are (deliberately) bland and faceless. I added some life to the people, and altered poses, and fashion to suit the squiggles of my pen.
I do seem to find this kind of squiggling very relaxing. And it can be quite suggestive of all sorts of things… Astrakhan, embroidery, hedges…