body {
  background-color: #111;
  color: #555;
  font-size: 1.1em;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

.container {
  margin: 50px auto;
  max-width: 640px;
  height: 400px;
  border: 1px solid #333;
}

img {
  margin: 20px auto;
  display: block;
  width: 640px;
  height: 400px;
  -webkit-mask-image: url(http://tympanus.net/codrops-playground/assets/images/cssref/properties/mask-position/mask-image.png);
  mask-image: url(http://tympanus.net/codrops-playground/assets/images/cssref/properties/mask-position/mask-image.png);
  -webkit-mask-position: top left;
  mask-position: top left;
  -webkit-mask-repeat: no-repeat;
  mask-repeat: no-repeat;
  -webkit-mask-size: 250px 250px;
  mask-size: 250px 250px;
}