- things = 10

mixin thing(n)
  if n > 0
    .thing
      +thing(n - 1)

.things
  - i = 1
  while i--
    +thing(things)

$s: 50vw;

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
}

.thing {
  display: flex;
  justify-content: center;
  align-items: center;
  margin: 1px;
  border: 10px solid transparent;
  border-color: tomato transparent transparent tomato;
  border-radius: 50%;
  animation: thing 5s cubic-bezier(0.35, -0.14, 0.79, 1.22) infinite;
}

@keyframes thing {
  100% {
    transform: rotateZ(1turn);
  }
}