yarn is held doubly.

cast on 18 and knit in the round. doing that repeat the following two rows:

row 1: knit 1 slip 1
row 2: knit all

finish after desired length has been achieved with row 1
cast off using crochet bind off

additionally, I crocheted the ends together, made a crochet chain of 26 stitches, and enforced it by single crochets back on each side combining them with a strand of single crochets along one of the slipped lines. It is all done without sewing and without any cuts to ensure durability.

The project will be part of a technological design at work.