<svg width='0' height='0'>
  <defs>
    <clipPath id='cp'  clipPathUnits='objectBoundingBox'>
      <path d='M1, .5 L.25, .067 L.25, .933 L1, .5 L.9, .5 L.3, .846 L.3, .154 L.9, .5z'/>
    </clipPath>
  </defs>
</svg>

<div class='clip-me'></div>

@import "compass/css3";

.clip-me {
  margin: 1em auto;
  width: 300px; height: 300px;
  background: #222;
  clip-path: url(#cp);
}