Shawl pins are for knitted, crocheted or loosely woven garments.
They should not be used on silk or any other fabric where a permanent hole would form.
I made several different styles, but the easiest one is made exactly like the previously published flower-link bracelet ( https://www.wirejewelry.com/jewelry_making_patterns_tutorials/Wire-Roses
Bracelet_380.html).
I use 14-gauge wire for these pins, as opposed to the 16-gauge for the bracelet.
The length of 14g wire needed depends upon the size of the loops and the center flower size.
I used 12" for the pin on the left and 10" for the one on the right.
When hammering the loops, I like to give them a slight curve which makes them easier to use on a garment.