specific folding method:
1. prepare a napkin
2. lay the napkin face down on the table.
3. Fold the napkin down from the upper third and up from the lower third to form a rectangle.
4. Fold the two ends of the rectangle to the middle, but not to the center, leaving a gap in the middle.
5. Fold the left bottom corner and the right top corner inward at an angle of 45, so that the two sides are aligned at the center line.
6. Turn the napkin upside down, turn the top of the napkin to the bottom, and let the loose corners turn out, with the four corners at the top.
7. Insert the right corner between the two inclined seams on the left.
8. Turn the napkin over and round the top.