mdbootstrap4-pro/mdb-addons/preloader.html

MDBootstrap 4 PRO

 <div class="preloader-wrapper big active">
     <div class="preloader-wrapper big active">
     <div class="preloader-wrapper big active">
   <div class="preloader-wrapper big active">
    <div class="spinner-layer spinner-blue-only">
      <div class="circle-clipper left">
        <div class="circle"></div>
      </div><div class="gap-patch">
        <div class="circle"></div>
      </div><div class="circle-clipper right">
        <div class="circle"></div>
      </div>
    </div>
  </div>
  </div>
  </div>
  </div>