JSFiddle - React, Tailwind, and code Playground

HTML

<div id="up-triangle"></div>
<div id="right-triangle"></div>

CSS

#up-triangle {
   width: 0; 
   height: 0; 
   border-bottom: 200px solid yellow; 
   border-left: 110px solid transparent; 
   border-right: 110px solid transparent; 
}

#right-triangle {
    position:absolute;
    top: 10px;
    left:175px;
    width: 50px; 
    height: 100px; 
    border-style: solid;
    border-width: 100px 0 0 300px; 
    border-color: transparent transparent transparent yellow;
    -webkit-transform: skew(29deg); 
   -moz-transform: skew(29deg); 
   -o-transform: skew(29deg);
   transform: skew(29deg);
}