This stitch is worked over a multiple of 8 stitches, plus and additional 3 stitcnes and worked over a 12 row repeat.

Purl the first row, this is a wrong side row.

To work the second row, knit the first 2 stitches. Then knit 1 stitch, knit 2 stitches together (right-leaning decrease), make a yarn over, knit 1 stitch, make another yarn over, slip 2 stitches, then knit them together (left-leaning decrease), then knit 2 stitches. These 8 stitches make the repeating pattern, repeat these 8 stitches until you have 1 stitch left of the row, knit the last stitch.

Purl the third row.

To work the 4th row, knit the first 2 stitches. Knit 2 stitches together (right-leaning decrease), make a yarn over, knit 3 stitches, make a yarn over, make a left-leaning decrease as before, knit 1 stitch. These 8 stitches make the repeating pattern, repeat these 8 stitches until you have 1 stitch left of the row, knit the last stitch.

Purl the 5th row.

To start work the 6th row, knit 1 stitch and make a right-leaning decrease. Make a yarn over, knit 5 stitches, make another yarn over, slip 1 stitch, knit 2 stitches together, then pass the slipped stitch over the decrease and off the needle to make a cental decrease. These 8 stitches make the repeating pattern, repeat these 8 stitches until you have 8 stitches left of your row. Make a yarn over, knit 5 stitches, make another yarn over, make a left-leaning decrease, knit the last stitch.

Purl the 7th row.

To work the 8th row, knit the first 2 stitches. Then make a yarn over, make a left-leaning decrease, knit 3 stitches, make a right-leaing decrease, make another yarn over, knit 1 stitch. These 8 stitches make the repeating pattern, repeat these 8 stitches until you have 1 stitch left of the row, knit the last stitch.

Purl the 9th row.

To work the 10th row, knit the first 2 stitches. Knit 1 stitch, make a yarn over, make a left-leaning decrease, knit 1 stitch, make a right-leaing decrease, make another yarn over, knit 2 stitches. These 8 stitches make the repeating pattern, repeat these 8 stitches until you have 1 stitch left of the row, knit the last stitch.

Purl the 11th row.

To work the 12th row, knit the first 2 stitches. Knit 2 stitches, make a yarn over, slip 1 stitch, knit 2 stitches together, pass the slipped stitch over the decrease and off the needle to make a central decrease, make another yarn over, knit 2 stitches. These 8 stitches make the repeating pattern, repeat these 8 stitches until you have 1 stitch left of the row, knit the last stitch.

These 12 rows form the Openwork Diamond pattern, continue repeating.