<div> with border-radius:50px.

<div> with border-top-left-radius: 50px;
border-top-right-radius: 50px;
border-bottom-right-radius: 50px;
border-bottom-left-radius: 50px;.

<div> with border-radius:20%.

<div> with border-radius:10px 40px 40px 10px.

<div> with border-radius:40px 10px.

<div> with border-radius:100px/30px.

<div> with border-radius:100px/30px.

<div> with border-radius:10%/60%.

<div> with border-radius:300px 100px 70px / 20px 25px 50px.

<div> with border-top-left-radius: 300px 20px;
border-top-right-radius: 100px 25px;
border-bottom-right-radius: 70px 50px;
border-bottom-left-radius: 100px 25px;.

<div> with border-radius:10px 5px 2em / 20px 25px 30%.

<div> with border-radius:27% 73% 70% 30% / 30% 34% 66% 70%.

<div> with border-top-left-radius: 27% 30%;
border-top-right-radius: 73% 64%;
border-bottom-right-radius: 70% 36%;
border-bottom-left-radius: 30% 70%;.