Trellis Slip stitch knitting.

Knitted in a multiple of 6, + 3 sts and a 8-row repeat.
Row 1 and all wrong side rows: Purl all sts.
Row 2 - Right side: K2, * sl 5 wyif, k1; rep from * to last st, k1.
Row 4: K4, * k1 uls, k5; rep from * to last 5 sts, k1 uls, k4.
Row 6: K1, sl 3 wyif, k1, * sl 5 wyif, k1; rep from * to last 4 sts, sl 3 wyif, k1.
Row 8: K1, * k1 uls, k5; rep from * to last 2 sts, k1 uls, k1.

Knitting abbreviations:
K: Knit | P: Purl | SL wyif: Slip stitch purlwise with yarn in front.
K1 uls: Knit 1 under loose strand.
- Insert right needle under loose strand and then into next stitch knitwise, from front to back. Knit stitch normally then bring new stitch out from under the strand.
Knit 1 under loose strand