Last fall, I took a hat class with Hillevi Huse on making wet-felted hats using resists in various forms. These hats are made from merino (mostly), with only two thin layers of fiber and a large shrinkage rate (probably around 50%).
I made this hat in class, it has a rosette on one side and a twisted horn on the other:


(merino, silk, and banana fibers)
This hat was also from class, it is merino with wensleydale locks, shaped sort of like an hourglass with the top (with lock) inverted over the bottom (no locks).

This one was me playing around with a resist at home, simple with just one rosette:

And another resist test (this resist needs some work), pixie hat with banana fibers. The resist is too long in back, among other things, although it looks a lot weirder on the hat form than on an actual person.

The last one I did using a glass washboard - very efficient for working all that shrinkage, but I need to find a better way to use it that doesn't result in painful welts on my palms....