Have fun with Cat Ears. These are easy to attach with a couple of pins. For a more seamless look the 3 loops facilitate sewing or attaching directly to your head or headband with a bobby pin. I went through a lot of prototypes.
The updated version has thicker loops so they don't disappear if you resize them. I also made the ear pointy on top.
I create these designs to encourage people to try out flexible filaments or get some new interesting colors of flexibles. For info on purchasing samples of 6 different types of flexible filament see flexyfilament.com