With size US 10_ (6.5mm) needles and 2 strands of A cast on 70 sts and knit 2 rows.
BEGIN STITCH PATTERN
Row 1: k1, * k2, p2; rep from * to last st, k1.
Row 2: k1, * p2, k2; rep from * to last st, k1.
Repeat Rows 1 and 2 until piece measures approximately 31 in [80cm], ending with row 2.
Knit 2 rows. Bind off all sts.
With 2 strands of B and size K crochet hook, work 1 round of slip stitch around edges of bathmat, then round of single crochet Weave in all ends.