JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

div {
    margin:20px;
    height: 200px;
    width: 200px;
    background-color: #c1c1c1; border:#000 solid 2px;
    background-image: 
        -webkit-linear-gradient(135deg, transparent 75%, #fff 75%),
        -webkit-linear-gradient(45deg, transparent 75%, #fff 75%);
    background-image: 
        -moz-linear-gradient(135deg, transparent 75%, #fff 75%),
        -moz-linear-gradient(45deg, transparent 75%, #fff 75%);
    background-image: 
        -ms-linear-gradient(135deg, transparent 75%, #fff 75%),
        -ms-linear-gradient(45deg, transparent 75%, #fff 75%);
    background-image: 
        -o-linear-gradient(135deg, transparent 75%, #fff 75%),
        -o-linear-gradient(45deg, transparent 75%, #fff 75%);
    background-image: 
        linear-gradient(135deg, transparent 75%, #fff 75%),
        linear-gradient(45deg, transparent 75%, #fff 75%);
    background-position: 30px 0, 0 0;
    background-repeat: no-repeat;
    background-size: 30px 30px;
}

JavaScript

//http://stackoverflow.com/questions/12619707/create-an-arrow-in-css3