Any yarn using a suitable needle size. The Heavier the yarn, the finished item will be heavier.
Cast-on 3 stitches.
Knit 4 rows GARTER STITCH
Increases are every 6 rows and on one side only.
When width is achieved, cast off 1 stitch every 6 rows.
Loopy edge is achieved by increasing 4 stitches, then on next row cast-off 3 of those new stitches. (Makes an increase of on stitch. )
Decreases similar. The decrease stitch is done K2TG, before the cast-on of 4 stitches and cast-off of the 3 stitches.