a:before,
a:after {
       content:'';
       display: block;
       width: 5px; height: 5px;
       position:absolute;
       top:21px;
       right: -5px;
   }	
   
a:before {background: #f3f3f2;}
a:after {
      background: #2e435e;
      -moz-border-radius-bottomleft: 5px;
      -webkit-border-bottom-left-radius: 5px;
      border-bottom-left-radius: 5px;
   }

I needed to create an inverted rounded corner. So I made this little CSS block to do it.

Make sure your absolute positioning the items where you want them.

And of course this does not work in IE.