<div class="box">
  <svg viewBox="0 0 240 200">
    <g class="path" fill="none" stroke="#fff" stroke-miterlimit="10" stroke-width="1">
    <path d="M0,0 C40,240 200,240 240,0" fill="none" stroke="#ffffff" stroke-dasharray="5 3"/>
    </g>
    <g class="path2">
      <path d="M0,200 C40,-40 200,-40 240,200" fill="none" stroke="#ff3399" stroke-dasharray="5 3">
    </g>
   </svg>
  <div class="pathed"></div>
  <div class="pathed anchor"></div>
</div>

@import url('https://fonts.googleapis.com/css?family=Gochi+Hand');

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


body {
  margin: 0;
  padding: 0;
  background-color: #291642;
  font-family: 'Gochi Hand', sans-serif;
  color: #fff;
  font-size: 130%;
  letter-spacing: 0.1rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 100vw;
  min-height: 100vh;
}

.box {
  width: 240px;
  height: 240px;
  border: 1px dashed #f36;
  margin-bottom: 2vh;
  position: relative;
}

.pathed {
  
  width: 10vh;
  height: 10vh;
  border: 1px solid hsla(343,100%,58%,.3);
  border-right: 5px solid hsl(343,100%,58%);
  background: hsla(343,100%,58%,.3);
  
  position: absolute;
  
  
  offset-path: path('M0,0 C40,240 200,240 240,0');
  
  
  animation:
    position 2000ms infinite alternate ease-in-out,
    distance 4000ms infinite alternate ease-in-out,
    rotate 3333ms infinite alternate ease-in-out,
    anchor 2000ms infinite alternate ease-in-out,
    path 6000ms infinite alternate ease-in-out;
  
  &::after {
    content: '';
    position: absolute;
    background: radial-gradient(circle at var(--anchorX) var(--anchorY), #fff 3px, transparent 3px) no-repeat;
    width: 100%;
    left: 0;
    bottom: 0;
    top: 0;
  }
  
  &.anchor {
    border-radius: 50%;
    border: none;
    width: 6px;
    height: 6px;
    background: #0fa99a;
  }
}

svg {
  position: absolute;
  opacity: .3;
}

@keyframes distance {
  100% {
    offset-distance: 100%;
  }
}

@keyframes rotate {
  0% {
    offset-rotate: auto 0deg;
  }
  100% {
    offset-rotate: auto 360deg;
  }
}

@keyframes anchor {
  0% {
    offset-anchor: 50% 50%;
  }
  40% {
    offset-anchor: -30% 80%;
  }
  100% {
    offset-anchor: 90% -20%;
  }
}

@keyframes path {
  100% {
    offset-path: path('M0,200 C40,-40 200,-40 240,200')
  }
}

@keyframes position {
  0% {
    offset-position: 0 0;
  }
  
  25% {
    offset-position: 25% 25%;
  }
  
  50% {
    offset-position: 50% 50%;
  }
  
  75% {
    offset-position: 75% 75%;
  }
  
  100% {
    offset-position: 100% 100%;
  }
}