Skirts wrinkle best on the back when they aren't tight. Some women sweep the back of their skirts or hold it against the back of their thighs as they sit down to keep the fabric from wrinkling. The women you see here didn't, their skirts hung down behind them and touched the seat and the fabric collapsed and folded under their butt and thighs when they sat down and wrinkles were crushed into it. After sitting for awhile, this was the result when she stood up.
This skirt looks like it was crumpled up in a suitcase or laundry bag. Skirt wrinkles look sexiest when they follow the natural contours of a woman's body, does this look as good as the other wrinkled skirts here?
A lovely extremely wrinkled miniskirt - linen, of course! The wrinkle patterns on skirts are unique to women's shapes (observe the different skirt wrinkles here), only about 1% of women's skirts are wrinkled this extremely. Here about 99% of them are, wrinkled skirt heaven!