Eyelet Lace 86: Old Shale Variation

PATTERN
Cast on a multiple of 18 stitches
Row 1 (RS): Knit.
Row 2: Purl.
Row 3: *[P2tog] 3 times, [yo, k1] 6 times, [P2tog] 3 times, repeat from *.
Row 4: Knit.
Repeat rows 1-4.
Worked in the round, see Eyelet Lace 86 in the round