This pattern uses American Standard Terms.
The chains at the beginning of each row do not count as a stitch.
I am a tight crocheter so be sure to use measurements or gauge swatch.
You will work your corner stitches in the CH 1 of the previous round’s corner stitch. I like to add a stitch marker after I make the CH 1 so I know exactly where to put it.
My finished cowl measurements before blocking: 14 inches long by 14 inches wide; neck opening is 8 inches
At the beginning of each round, you will work in the same ST as your chain in all of the rounds until you SLST to join, then for the remaining rounds, you will be working into the next ST. You can easily adjust this pattern to create a shawl. Just keep repeating Rounds 20, 21, 22, and 23 in that order and without joining until you are close to the size you want, and then start working Rounds 24 through 30.
If you want to make a shawl instead of a cowl, do not slip stitch to join (starts at Round 19). Just ignore the slip stitch instructions that start at Round 19 and keep repeating Rounds 20, 21, 22, and 23 in that order until you are almost to the shawl size you want and then start working Rounds 24-30. For a shawl, I would work Rounds 24-30 at least twice.