body {
  font-family: Avenir, sans-serif;
  margin: 0;
  background-color: #121;
}
div#quad {
  background-color: #000;
  font-size: 0;
  width: 60%;
  margin: 0 auto;
  box-shadow: 0 0 12px rgba(0, 0, 0, 0.8);
}
div#quad figure {
  margin: 0;
  width: 50%;
  height: auto;
  transition: 1s;
  display: inline-block;
  position: relative;
  overflow: hidden;
}
div#quad figure:hover {
  cursor: pointer;
  z-index: 4;
}
div#quad figure img {
  width: 100%;
  height: auto;
}
div#quad figure:nth-child(1) {
  transform-origin: top left;
}
div#quad figure:nth-child(2) {
  transform-origin: top right;
}
div#quad figure:nth-child(3) {
  transform-origin: bottom left;
}
div#quad figure:nth-child(4) {
  transform-origin: bottom right;
}
div#quad figure figcaption {
  margin: 0;
  opacity: 0;
  background: rgba(0, 0, 0, 0.3);
  color: #fff;
  padding: 0.3rem;
  font-size: 1.2rem;
  position: absolute;
  bottom: 0;
  width: 100%;
  transition: 1s 1s opacity;
}
.expanded {
  transform: scale(2);
  z-index: 5;
}
div#quad figure.expanded figcaption {
  opacity: 1;
}
div.full figure:not(.expanded) {
  pointer-events: none;
}