How to center blocks in bootstrap?

Question

Bootstrap

<div class="container">
     <div class="row">
           <div class="col-lg-3 col-md-3 col-sm-6 col-xs-12"></div>
           <div class="col-lg-3 col-md-3 col-sm-6 col-xs-12"></div>
           <div class="col-lg-3 col-md-3 col-sm-6 col-xs-12"></div>
           <div class="col-lg-3 col-md-3 col-sm-6 col-xs-12"></div>
           <div class="col-lg-3 col-md-3 col-sm-6 col-xs-12"></div>
           <div class="col-lg-3 col-md-3 col-sm-6 col-xs-12"></div>
           <div class="col-lg-3 col-md-3 col-sm-6 col-xs-12"></div>
     </div>
</div>

By default, the blocks become like this:

And how to place them in the center, like this:

Well, what would it be adaptive.

Answer 1

for example