Two-Colour Diagonal Weave. Like all slip stitches, it compresses in height, so it's good for warm outerwear.

With color A, cast on a multiple of 4 sts + 1.
Row 1 (WS): With color A, purl all sts.
Row 2 (RS): With color B, knit 1, * slip 1 wyib, knit 3; repeat from * to end.
Row 3: With color B, * purl 3, slip 1 wyif; repeat from * to last st, purl 1.
Row 4: With color A, knit 1,* drop next slip st off left -hand needle to front of work, knit 2, then pick up dropped st and knit it, knit1; repeat from * to end.
Row 5: With color A, purl all sts.
Row 6: With color B, knit 5, * slip 1 wyib, knit3; repeat from * to end.
Row 7: With color B, * purl 3, slip 1 wyif; repeat from * to last 5 sts, purl 5.
Row 8: With color A, knit 3, * slip 2 wyib, drop next slip st off left -hand needle to front of work, slip the same 2 sts back to the left-hand needle, then pick up dropped st and knit it, knit3; repeat from * to last 2 sts, knit 2.
Repeat rows 1 to 8 till necessary for completing your project.

Note: With yarn in back: wyib  |  With yarn in front: wyif.