Suffocate

<div></div>
<div></div>
<div></div>
<div></div>
<style>
  body {
    background: #1a4341;
    margin: 0;
    display: flex;
    flex-wrap: wrap;
  }
  div {
    width: 50%;
    height: 50%;
    background: #f3ac3c;
  }

  div:nth-child(1) {
    border-radius: 0 0 100px 0;
  }
  div:nth-child(2) {
    border-radius: 0 0 0 100px;
  }
  div:nth-child(3) {
    border-radius: 0 100px 0 0;
  }
  div:nth-child(4) {
    border-radius: 100px 0 0 0;
  }
</style>