I knit the cap from a photo from Pintetest. When it was ready, it turned out it’s a modified version of a pattern by Katrin Schubert.

IMHO, the beauty of the pattern lies in a slight bulge of the round structural pieces (not obvious in the photos).

(Now the cap’s completed, washed & drying, and better images to come soon.)

MIGHT BE USEFUL: since I’m extremely bad at purling, I reversed the direction of knitting after every sub-row & thus knit the other sub-row (of a pair) instead of purling it. There is another benefit of such an approach: you face alternatively either side of the knitting and have a chance of spotting possible mistakes (slipped yarn-overs) much sooner than with the traditional method.