.U{
position:relative;
left:10px;
top:12.5px;
width:60px;
height:80px;
border-width:0 16px0 16px;
border-color:#000000;
border-style:solid}

.U::before{
position:absolute;
content:'';
left:-16px;
top:65px;
width:60px;
height:45px;
border-width:0 16px15px16px;
border-color:#000000;
border-style:solid;
border-radius:0 0 200%200% /0 0 300%300%}