#container {
  --n:7;   /* number of item */
  --d:12s; /* duration */

  width: 200px;
  height: 200px;
  margin: 40px auto;
  border: 1px solid #000;
  display:grid;
  grid-template-columns:30px;
  grid-template-rows:30px;
  place-content: center;
  border-radius: 50%;
}
.item {
  grid-area:1/1;
  line-height: 30px;
  text-align: center;
  border-radius: 50%;
  background: #f00;
  animation: spin var(--d) linear infinite; 
  transform:rotate(0) translate(100px) rotate(0);
}
@keyframes spin {
  100% {
    transform:rotate(1turn) translate(100px) rotate(-1turn);
  }
}

.item:nth-child(1) {animation-delay:calc(-0*var(--d)/var(--n))}
.item:nth-child(2) {animation-delay:calc(-1*var(--d)/var(--n))}
.item:nth-child(3) {animation-delay:calc(-2*var(--d)/var(--n))}
.item:nth-child(4) {animation-delay:calc(-3*var(--d)/var(--n))}
.item:nth-child(5) {animation-delay:calc(-4*var(--d)/var(--n))}
.item:nth-child(6) {animation-delay:calc(-5*var(--d)/var(--n))}
.item:nth-child(7) {animation-delay:calc(-6*var(--d)/var(--n))}
.item:nth-child(8) {animation-delay:calc(-7*var(--d)/var(--n))}
.item:nth-child(9) {animation-delay:calc(-8*var(--d)/var(--n))}
/*.item:nth-child(N) {animation-delay:calc(-(N - 1)*var(--d)/var(--n))}*/

class CircularQueue:
    def __init__(self, size):
        self.size = size
        self.head = 0
        self.tail = 0
        self.buffer = [None] * size
        self.length = 0

    def enqueue(self, value):
        self.length += 1
        self.buffer[self.tail] = value
        self.tail += 1
        if self.tail >= self.size:
            self.tail = 0

    def dequeue(self):
        self.length -= 1
        value = self.buffer[self.head]
        self.head += 1
        if self.head >= self.size:
            self.head = 0
        return value

@mixin circle($width,$height,$color) {
    width: $width;
    height: $height;
    background: $color;
    border-radius: 50%;

}