With B, cast on 40 sts. Work in Garter st for 2 inches [5 cm]. Change to A and continue in Garter st until piece measures 10 inches [25.5 cm] from beginning.
Row 1 *K 2, k2tog; repeat from * across – 30 sts.
Row 2 *K 1, k2tog; repeat from * across – 20 sts.
Rows 3-5 *K2tog; repeat from * across – 3 sts at end of Row 5.
Break yarn leaving a 24 inches [61 cm] tail. Thread tail onto large-eyed, blunt needle and draw through remaining sts. Pull tight and secure; sew side seam; weave in ends.
With A, cast on 13 stitches. Working in Garter Stitch, knit 2 rows with A, then 2 rows with B. Do not cut yarn when changing colors; carry the unused color loosely along the side. Continue knitting 2 rows in each color until approximately 24 inches [61 cm] of yarn remains. Bind off all stitches loosely. Weave in ends