With one strand of worsted-weight and one strand of baby-weight, cast on an odd number of stitches.
Foundation Row: Knit (note: this row is not repeated).
Row 2 (right side): Sl 1, * K1B, p1; rep from * to end. (editor's note: I found that knitting the last stitch instead of purling gives a nicer edge.)
Row 3: Sl 1, * p1, K1B; rep from * to last 2 sts, p1, k1.
Repeat rows 2 and 3 until desired length. Finish off.