3D transforms can be use to create many 3D shapes. Here is a simple 3D CSS cube example:

HTML:

<div class="cube">
  <div class="cubeFace"></div>
  <div class="cubeFace face2"></div>
</div>

CSS:

body {
  perspective-origin: 50% 100%;
  perspective: 1500px;
  overflow: hidden;
}
.cube {
  position: relative;
  padding-bottom: 20%;
  transform-style: preserve-3d;
  transform-origin: 50% 100%;
  transform: rotateY(45deg) rotateX(0);
}
.cubeFace {
  position: absolute;
  top: 0;
  left: 40%;
  width: 20%;
  height: 100%;
  margin: 0 auto;
  transform-style: inherit;
  background: #C52329;
  box-shadow: inset 0 0 0 5px #333;
  transform-origin: 50% 50%;
  transform: rotateX(90deg);
  backface-visibility: hidden;
}
.face2 {
  transform-origin: 50% 50%;
  transform: rotatez(90deg) translateX(100%) rotateY(90deg);
}
.cubeFace:before, .cubeFace:after {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  transform-origin: 0 0;
  background: inherit;
  box-shadow: inherit;
  backface-visibility: inherit;
}
.cubeFace:before {
  top: 100%;
  left: 0;
  transform: rotateX(-90deg);
}
.cubeFace:after {
  top: 0;
  left: 100%;
  transform: rotateY(90deg);
}

View this example

Additional styling is added in the demo and a transform is applied on hover to view the 6 faces of the cube.

Should be noted that: