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console

            
<svg viewBox="0 0 340 333">

  <path class="path" fill="none" stroke="black" stroke-width="4" d="M30,10 L200,10 L200,150"/>
  
</svg>

            
.path {
  stroke-dasharray: 10;
  animation: dash 5s linear infinite;
}

@keyframes dash {
  0% {
    stroke-dashoffset: 0;
  }
  100% {
    stroke-dashoffset: 200;
  }
}