Only the odd rows of the pattern are listed, for the even rows simply do your garter stitch border and knit the knits and purl the purls.
Cast on 36 stitches
Knit four rows of garter stitch
1. K4, P12, K4, P12, K4
3. K4, P11, LC, RC, P11, K4
5. K4, P10, LC, P2, RC, P10, K4
7. K4, P9, LC, P4, RC, P9, K4
9. K4, P8, LC, P6, RC, P8, K4
11. K4, P7, LC, P8, RC, P7, K4
13. K4, P6, LC, P10, RC, P6, K4
15. K4, P5, LC, P12, RC, P5, K4
17. K4, P4, LC, P14, RC, P4, K4
19. K4, P3, LC, P16, RC, P3, K4
21. K4, P2, LC, P18, RC, P2, K4
23. K4, P3, RC, P16, LC, P3, K4
25. K4, P4, RC, P14, LC, P4, K4
27. K4, P5, RC, P12, LC, P5, K4
29. K4, P6, RC, P10, LC, P6, K4
31. K4, P7, RC, P8, LC, P7, K4
33. K4, P8, RC, P6, LC, P8, K4
35. K4, P9, RC, P4, LC, P9, K4
37. K4, P10, RC, P2, LC, P10, K4
39, K4, P11, RC, LC, P11, K4
41. K4, P12, slide 2 to cable needle and hold to front, K2, K2 from cable needle, P12, K4
Repeat pattern from row 3 to desired length. On the final diamond, omit row 41.
To finish knit 4 rows of garter stitch and bind off.
LC = Left Cable: slide 1 to cable needle, hold to back, knit 2, purl 1 from cable needle
RC = Right Cable: slide 2 to cable, hold to front, purl 1, knit 2 from cable needle
This pattern looks very confusing, but once you understand the flow it is simple. For each (odd) row that your diamond is widening you are moving one purled stitch from the outside of the right of the diamond and one purled stitch from the outside of the left of the diamond to the inside. This is what makes it widen. For each (odd) row that your diamond is narrowing you are moving one purled stitch from the inside right of the diamond and one purled stitched from the inside left of your diamond to the outside. This is what makes it narrow.
The purled stitch that is getting moved always goes under or behind the two knitted stitches during the move. (Another way to say this is that the two knitted stitches always go over or in front of the purled stitch.) The act of moving the knitted stitches over the purled stitch (or the purled stitch under the knitted stitches) is what makes the diamonds stand up off of the fabric.
I did not use a cable needle for crossing my stitches over each other. The less time-consuming method I used can be found in the "Crossing Cables without a cable needle" video on this site: http://www.knittinghelp.com/videos/advanced-techniques For a left cable I slid my right hand needle into the front of the two knitted stitches (in front of the purled stitch) and slipped them over, reinserted the left hand needle into the purled stitch, and slipped the knitted stitches back onto the left hand needle. For a right cable I slid my right hand needle into the back of the purled stitch (behind the knitted stitches) and slipped it over, reinserted the left hand needle into the knitted stitches, and slipped the purled stitch back onto the left hand needle. For me it was helpful to gently pinch beneath the stitches before slipping so that the stitch or stitches being moved didn't drop.
Note: I have not tested this pattern to make sure the garter stitch border is enough to make it lay flat. I also wrote up this pattern after making the scarf, rather than before, so if you find any errors, please leave a comment. Also, I am half self-taught when it comes to knitting and for several of my first projects I knit into the back of the loop rather than the front. At least one diamond cable pattern I looked at before designing this scarf specified to do so, so it my help the diamonds to stand up off the fabric more.
