Knotted Pillar Stitch aka Reversible Mock Crochet

Sample knit with Patons Grace Cotton Yarn on US 6 Knitter's Pride Nova Cubics

Multiple of 4 + 1

Row 1: (RS) k1 *p3tog, leaving sts on needle, k3tog, leaving sts on needle, then p3tog once more before slipping sts off needle, k1.  Repeat from * to end

Row 2: purl

Repeat these two rows for the pattern.