<div class="cube-big">
  <div class="big">
    <span style="--i:0;--clr:#e2e2e2;"></span>
    <span style="--i:1;--clr:#f0f0f0;"></span>
    <span style="--i:2;--clr:#e2e2e2;"></span>
    <span style="--i:3;--clr:#f0f0f0;"></span>
    <span class="top" style="--clr:#fff;"></span>
  </div>
</div>
<div class="cube-samll">
  <div class="big">
    <span style="--i:0;--clr:#08c9e2;"></span>
    <span style="--i:1;--clr:#00a6bc;"></span>
    <span style="--i:2;--clr:#08c9e2;"></span>
    <span style="--i:3;--clr:#00a6bc;"></span>
    <span class="top" style="--clr:#6fdfee;"></span>
  </div>
</div>

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #222;
}

.cube-big {
  position: absolute;
  width: 300px;
  height: 300px;
}

.cube-big div {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  animation: animate 6s linear infinite;
}

@keyframes animate {
  0% {
    transform: rotateX(-20deg) rotateY(360deg);
  }
  
  100% {
    transform: rotateX(-20deg) rotateY(0deg);
  }
}

.cube-big div.big span {
  position: absolute;
  top: 80px;
  width: 300px;
  height: 300px;
  background: var(--clr);
  transform: rotateY(calc(90deg * var(--i))) translateZ(150px);
  transform-style: preserve-3d;
  transition: 0.5s;
}

.cube-big:hover div.big span {
  background: transparent;
  border: 10px solid #00a6bc;
  filter: drop-shadow(0 0 20px #00a6bc);
}

.cube-big div.big span.top {
  transform: rotateX(90deg) translateZ(150px);
}

.cube-big div.big span.top::before {
  content: '';
  position: absolute;
  inset: 0;
  transform: translateZ(-350px);
  background: rgba(0,0,0,0.5);
  filter: blur(50px);
}

.cube-samll {
  position: absolute;
  width: 300px;
  height: 300px;
  top: 50%;
  left: 50%;
  transform: translate(-50%,-350px);
}

.cube-samll div {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  animation: animate2 6s linear infinite;
  scale: 0.5;
}

@keyframes animate2 {
  0% {
    transform: rotateX(-20deg) rotateY(0deg);
  }
  
  100% {
    transform: rotateX(-20deg) rotateY(360deg);
  }
}

.cube-samll div.big span {
  position: absolute;
  top: 80px;
  width: 300px;
  height: 300px;
  background: var(--clr);
  transform: rotateY(calc(90deg * var(--i))) translateZ(150px);
  transform-style: preserve-3d;
  transition: 0.5s;
}

.cube-big:hover ~ .cube-samll div.big span {
  background: transparent;
  border: 10px solid #fff;
  filter: drop-shadow(0 0 20px #fff);
}

.cube-samll div.big span.top {
  transform: rotateX(90deg) translateZ(150px);
}

.cube-samll div.big span.top::before {
  content: '';
  position: absolute;
  inset: 0;
  transform: translateZ(-350px);
  background: rgba(0,0,0,0.35);
  filter: blur(50px);
}