<div class="fancy"></div>

body {
  height:100vh;
  margin:0;
  display:grid;
  place-items:center;
  place-content:center;
  background:#3a1a3b;
  overflow:hidden;
}

.fancy {
  width:50px;
  height:50px;
  display:grid;
  position:relative;
  border:5px solid #efab5f;
  transform:rotate(45.5deg);
  filter:drop-shadow(108px 0 0 #efab5f) drop-shadow(216px 0 0 #efab5f) drop-shadow(432px 0 0 #efab5f) drop-shadow(-864px 0 0 #efab5f) drop-shadow(0 -108px 0 #efab5f) drop-shadow(0 -216px 0 #efab5f) drop-shadow(0 -432px 0 #efab5f) drop-shadow(0 864px 0 #efab5f);
  animation:b 5s infinite alternate;
}
.fancy:before,
.fancy:after{
  content: "";
  position: absolute;
  inset: -24px auto auto -24px;
  width: 66.66%;
  height: 66.66%;
  border-radius: 0 50%;
  border: 5px solid #efab5f;
  filter: drop-shadow(55px 55px 0 #efab5f);
  animation:a 3s infinite alternate;
}
.fancy:after{
  inset: -24px -24px auto auto;
  filter: drop-shadow(-55px 55px 0 #efab5f);
  border-radius: 50% 0;
  animation-delay:-2s;
}

@keyframes a {
  0%,30%{border-radius:50% 0}
  70%,100%{border-radius:0 50%}
}
@keyframes b {
  0%,50%{border-radius:0}
  80%,100%{border-radius:50%}
}