<style type="text/css">
.triangle b {
    border: 5px solid #fff;
    border-left: 5px solid #353535;
    margin: 0;
    font-size: 0;
}
</style>

<style type="text/css">
 .mark b{border:solid #D0D0D0;width:6px;height:6px;display:inline-block;}
 .mark  b.lmark{border-width:2px 2px 0 0;transform: rotate(45deg);}
 </style>

 	*{
		padding:0;
		margin:0;
	}

	div:before{
		content:"";
		width:20px;
		height:20px;
		position:absolute;
		top:-10px;
		left:40px;
		border-radius:50%;
		background-color:white;
	}

	div{
		position:relative;
		width:100px;
		height:100px;
		margin:100px auto;
		box-shadow:0 0 2px red;
		background-color:#ccc;
	}