JSFiddle - React, Tailwind, and code Playground

HTML

<menu type=list>
    <li>home</li> 
    <li>work</li>  
</menu>

CSS

menu{
   position:relative;
   width:320px;
   height:40px;
}

li{
    float:left;
    width:50%;
    background-color:red;
    list-style:none;
    position:relative;
    height:54px;
    text-align:center;
    line-height:50px;
    color:white;
}

li:before,li:after{
    position:absolute;
    content:"";
    height:40px;
    width:40px;
    border-radius:4px;
    background-color:red;
    top: 7px;
    -webkit-transform:rotate(45deg);
    -moz-transform:rotate(45deg);
    transform:rotate(45deg);
}
li:before{
    left:-20px;
}
li:after{
    right:-20px;
}
li:nth-child(2):before{
    box-shadow: 0px 0 0 black,-4px 4px 0 black;
}