Knit Purl 31 in the round

PATTERN IN THE ROUND
Cast on a multiple of 4 stitches.
Rounds 1-2: Knit.
Round 3: *Knit 1, purl 3, repeat from *.
Round 4: *Purl 1, knit 3, repeat from *.
Repeat rounds 1-4.

Worked flat, see Knit Purl 31: Ridge Rib stitch