3. At this point, you’ll start decreasing.
Knit two stitches together to the end of the row on the 19th row, leaving 12 stitches.
When you knit two stitches together to the end of the 20th row, you will have 6 stitches remaining.
Knit two stitches together to the end of the row on the twenty-first row, leaving three stitches.
4. Trim the yarn, leaving a 30-cm tail, and pass it through the last few stitches on your needle.
5. To create an empty round cactus, bring the two ends together and sew them. To bring the top of the cactus together, take out the knitting needle and tug on the yarn tail.