I made a neat shape yesterday called a humybug. I'd never done one before. Followed the tutorial here: https://plushcat.blogspot.com/p/humbug-tutorial.html. You start with a rectangle and sew it into a little tetra shape. It's cute. I think it would make a good cat toy. :)
Cool! Post a picture if you make one. It's a little fiddly at the end, but fun and quick to make.
I used a random scrap of some terrible thick stuff from joann's. My advice would be to use a thinner piece of Aida or evenweave, or make a bigger rectangle. The corners were really difficult to squish shut.