This technique is called ribbing, which is another combination of knitting and purling.
The written pattern for this would be:
Row 1: *k2, p2. Repeat from * across.
Row 2: *p2, k2. Repeat from * across.
Repeat Rows 1 and 2 until piece is desired length.
Step 1: Cast On
For this pattern, I cast on 16 stitches.
Step 2: Knit 2 Stitches
Step 3: Bring Yarn Between Needles to Front of Work.
Step 4: Purl 2 Stitches.
Step 5: Bring Yarn Between Needles to Back of Work.
Step 6: Repeat Across.
Always bring the yarn between the needles on the side that you need it.
If you're knitting, the yarn will be in the back.
If you're purling, the yarn will be in the front.
There will be 2 stitch repeats. For my 16 sts, it looked like: k2, p2, k2, p2, k2, p2, k2, p2.
Then after you turn your work, you do the opposite, so for my 16 sts, it looked like: p2, k2, p2, k2, p2, k2, p2, k2.
Step 7: In Progress
You will see these vertical lines, with the knitted ones, or v's, standing out.
This makes the material very stretching and is why this stitch is used for a lot of hats and sweater edges.
Again, you count how many v's there are in a column to determine how many rows you have worked.
Step 8: Finished Product
And you're done! You can bind off the same way, or there are ribbed bind-offs that you can find on the internet that are better at keeping the edge looking like the ribbing. Leave comments!