At first glance this stitch looks quite fiddly and difficult but, working with only one yarn at a time makes it much easier than it looks. Using a variegated yarn underneath and a contrasting solid or semi-solid yarn for the grid works very well, but the results using two similar yarns are also lovely because of the wonderful texture it creates. You can change the pattern of your grid by working more or fewer stitches between the elongated grid stitches and the garter ridges, just remember that if you have more rows between the garter ridges then you will need more wraps on the elongated stitches.
You will need
ColourSpun yarn of your choice: main colour – A, Grid colour – B
Knitting needles to suit your yarn
ES Elongated stitch – knit, wrapping the yarn around the needle twice
S1 slip next stitch (for this pattern it will be the elongated stitch, slip it from the left needle to the right, allowing the extra wrap to fall away.
With colour B, cast on a number of stitches divisible by 4 + 3
[Note: if you change the grid pattern, the number of stitches cast on will also change]
Row 1 (colour B): K3 (ES, K3) repeat to end of row.
Row 2 and 4 (colour A): K3 (S1, K3) repeat to end of row.
Rows 3 and 5 (colour A): P3 (S1, P3) repeat to end of row.
Row 6 (colour B): Knit
Repeat rows 1 to 6 to desired length. End after row 5.
Cast off with colour B.