test

 <div class="row">
     <div class="col-lg-6 col-md-12 border cell"> . </div>
     <div class="col-lg-6 col-md-12 border cell"> . </div>
 </div>
 <div class="row">
     <div class="col-lg-12 cell1">.</div>
 </div>
 <div class="row">
     <div class="col-lg-4 col-md-12 cell2 border">.</div>
     <div class="col-lg-4 col-md-12 cell2 border">.</div>
     <div class="col-lg-4 col-md-12 cell2 border">.</div>
 </div>
 <div class="row">
     <div class="col-lg-3 col-md-6 cell3 border">.</div>
     <div class="col-lg-3 col-md-6 cell3 d-none d-md-block border">.</div>
     <div class="col-lg-3 col-md-6 cell3 d-none d-md-block border">.</div>
     <div class="col-lg-3 col-md-6 cell3 d-none d-md-block border">.</div>
 </div>