Trinity stitch also known as Cluster 3 stitch, Bramble stitch, Raspberry stitch.

Knitted in a multiple 4 sts, and 4-row repeat.
Row 1 (Right side): Purl all sts.
Row 2: * (Knit 1, purl 1, knit 1) all in the same st, purl 3 sts together; repeat from * to end.
Row 3: Purl all sts.
Row 4: * Purl 3 sts together, (knit 1, purl 1, knit 1) all in the same st; repeat from * to end.