<div class="shape"></div>
<div class="shape"></div>

:nth-child(1 of .shape) {
  clip-path: shape(from 0 0,
    arc to 100% 100% of 100% cw,
    line to 0 100%);
  background: rgb(255 0 0/50%);
}
:nth-child(2 of .shape) {
  clip-path: shape(from 0 0,
    curve to 100% 100% with 100% 0,
    line to 0 100%);
  background: rgb(0 255 255/50%);
}


.shape {
  width: 300px;
  aspect-ratio: 1;
  grid-area: 1/1;
  margin: 10px;
}


body {
  margin: 0;
  display: grid;
}