I'm the boss (of my stitches at least....)
The pattern is listed as DK, but it’s very flexible - suggested stitch counts are given for fingering-aran weights.
The actual stitch is called Embossed Wave, but I knitted this while my house was covered with scaffolding and workers and chaos were in abundance - I found “controlling” the stitches was just what I needed to unwind in the evening (so embossed became I’m the boss).
I find making the stitches move back and forth more relaxing than just knitting garter stitch.
The little bit of counting becomes very meditative.
The increases and decreases are worked on separate rows, so you only have to concentrate on one thing per row.
And 2 out of every 10 rows are “rest rows”.
It looks like cables, but no cable needle is needed.
Many thanks to the testers: