console
<div id="list">
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
<div class="item"></div>
</div>
#list{
display: flex;
flex-wrap: wrap;
transition: all .5s ease;
}
.item{
width: 120px;
height: 120px;
background: gray;
margin: 10px;
transition: all .5s ease;
position: relative;
}
.item:nth-child(2n){
background: #d0d0d0;
}