This is the matching insertion to the Apple Leaf Edging from 1889 Weldon’s Practical Needlework, Volume 2 but Weldon’s calls it “Diamond Insertion”. There are only 15 stitches to cast on. Every row begins the same and ends the same for the headers; only the middle section changes. I changed the selvage stitches for easier sewing later.
Skills: cast on, knit, purl, slip, k2tog, k3tog, SKP (slip1-knit1-PSSO), yarn over and bind off in knit stitch.

Gauge is not important in this pattern. Any block-able thread/yarn will work. Make a swatch to check for size and appearance.

Yardage: 11 yards will make about 1 repeat (1.5 inches) of insertion in the stated gauge with #10 crochet cotton