rotary knob

by Felis Catus

HTML

<div class='roochka'>

</div>

CSS

.roochka{
  background-color: teal;
  position: absolute;
  width: 100px;
  height: 100px;
  border-radius: 100px;
  top: 50px;
  left: 50px;
  filter: drop-shadow(0 0 3px silver) drop-shadow(0 0 0 silver) drop-shadow(0 0 0 silver) drop-shadow(0 0 0 silver) drop-shadow(0 0 0 silver);
  transform: rotate(75deg);
}
.roochka:after {
  position: absolute;
  width: 20px;
  height: 20px;
  top: 6px;
  left: 6px;
  content: '';
  background: inherit;
}
body { background: white; }