JSFiddle - React, Tailwind, and code Playground

HTML

<div id="pfeil">
    <div class="shape1"></div>
    <div class="shape2"></div>
</div>

CSS

#pfeil {
    width: 50px;
    height: 50px;
    position: relative;
    margin-left: 10px;
}
#pfeil .shape1, #pfeil .shape2 {
    border-width: 40px;
    border-style: solid;
    height: 0;
    width: 0;
    border-color: #000 transparent transparent transparent;
    top: 10px;
    position: absolute;
}

#pfeil .shape2 {
    top: 0px;
    border-color: #fff transparent transparent transparent;
}