Is it possible to make custom shaped CSS buttons?

Question

I want to make a button that goes on the left side of the screen that looks something like this:

Image

Is this possible in CSS?

So far I have tried using border-top-right-radius combined with border-bottom-right-radius expecting them to meet in the middle and make the semicircle but intead only made a square with one curved line going from one corner to another.

Answer 1

button {
  width: 50px;
  aspect-ratio: 1 / 2;
  
  border-radius: 0 100vw 100vw 0;
}

<button>></button>

There you go :D