.el {
  width: 200px;
  height: 200px;
  border: 6px solid black;
  border-radius: 24px;
  background: repeating-conic-gradient(
    at -5% 105%,
    red 0 2.5%,
    yellow 2.5% 5%
  );
}
body {
  height: 100vh;
  margin: 0;
  display: grid;
  place-items: center;
}