#hexagon {
	width: 100px;
	height: 55px;
	background: red;
	position: relative;
}
#hexagon:before {
	content: "";
	position: absolute;
	top: -25px;
	left: 0;
	width: 0;
	height: 0;
	border-left: 50px solid transparent;
	border-right: 50px solid transparent;
	border-bottom: 25px solid red;
}
#hexagon:after {
	content: "";
	position: absolute;
	bottom: -25px;
	left: 0;
	width: 0;
	height: 0;
	border-left: 50px solid transparent;
	border-right: 50px solid transparent;
	border-top: 25px solid red;
}