JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box-cover">
<div class="small_box_right">

</div>
<div class="small_box_right">

</div>
<div class="small_box_right">

</div>
<div class="small_box_right">

</div>

</div>

CSS

.box-cover{
        position: relative;
        height: 300px;
        overflow: scroll;
        width: 1550px;
    }

    .small_box_right {
        position: relative;
        display:inline-block;
        background: #CDCDB4;
        border: 4px solid black;
        height:300px;
        width:300px;
        margin-right: 50px;
    }
    .small_box_right:after, .small_box_right:before {
        left: 100%;
        top: 50%;
        border: solid black;
        content: " ";
        height: ;
        width: ;
        position: absolute;
        pointer-events: none;
    }
    .small_box_right:after {
        border-color: rgba(136, 183, 213, 0);
        border-left-color: #CDCDB4;;
        border-width: 30px;
        margin-top: -30px;
    }
    .small_box_right:before {
        border-color: rgba(194, 225, 245, 0);
        border-left-color:black ;
        border-width: 36px;
        margin-top: -36px;
    }