To crochet a dish towel topper, single crochet across the dish towel's top to create a base row using a crochet hook of size F. Then, use chain and double crochet stitches in a specific pattern to make 13 rows of the topper and its narrow strip.
After making the base row, chain three stitches, turn the piece and double crochet in every single crochet stitch. Again, chain three stitches, turn, double crochet in the next stitch, skip the next stitch, double crochet in the next two stitches, and again, skip the next stitch. Repeat this step across. For the next two rows, chain three stitches, turn, and alternatively skip and double crochet in existing stitches.
To make the topper's narrow strip, chain three stitches, turn, and double crochet eight stitches so that they are spaced evenly across the row. For the next six rows, chain three stitches, turn, and make double crochet stitches in the existing stitches.
Then, chain three stitches again, double crochet in the next three stitches, chain one, skip one stitch, and double crochet in the next four stitches to make the buttonhole. For the last row, chain three stitches, turn, double crochet in the next three stitches, in the chain one space and in the next four stitches, successively.
Finally, fold the narrow strip over, and affix a button under the buttonhole created. Use a four-ply yarn of a suitable color for crocheting.