Initially, found a photo of the cowl on Pinterest & knit the cap from it. Later, found the design on ravelry.com.

Cast on 80 stitches (four repeats of the pattern), which is ~ usual number of stitches for brioche caps, given my yarn/needle combination & gauge. However, in this case it turned out too few (should have been a hundred stitches = five repeats of the pattern). My limited experience with brioche knitting doesn’t allow to predict the gauge by seeing the pattern.
A syncopated brioche pattern with lots of star stitches and a few brioche L & R decreases.