This very simple pattern is from 1902 Butterick’s Fancy and Practical Knitting, p.7, No.6. “Semi-Double Knitting” is Butterick’s original name for this pattern. Any number of stitches will work and there are only 2 rows to the pattern: increase in every stitch in the first row, decrease in every stitch in the second row. The 2 selvage stitches are optional. I went up 2 needle sizes (U.S. #9 instead of #7) due to the intense increasing in the first row. Do the same, if needed.
This stitch pattern makes a thick, dense knitted fabric: perfect for potholders, pads, blankets or even as gambesons for LARP events.

Skills needed: cast on, purl and knit in 1 stitch, k2tog and bind off in knit stitch.

Gauge is not important in this pattern. Any yarn/thread will work. Make a swatch to check gauge and appearance.

65 yards of Lion brand 24/7 yarn will make 10 inches of a 22-stitch-wide strip at gauge.