<div class="outerContainer">
  The square is moving from side to side while the perspective-origin is centered
  <div class="container containerA">
    <div class="square"></div>
  </div>
</div>

<div class="outerContainer">
  The square is centered while to perspective-origin is moving from side to side
  <div class="container containerB">
    <div class="square"></div>
  </div>
</div>

@import url("https://fonts.googleapis.com/css2?family=Anton&display=swap");

*, *::before, *::after {
  padding: 0;
  margin: 0 auto;
  box-sizing: border-box;
}

body {
  font-family: 'Anton', sans-serif;
  background-color: #eee;
  color: #333;
  min-height: 100vh;
  display: -webkit-box;
  display: flex;
  -webkit-box-pack: center;
          justify-content: center;
  align-content: center;
  -webkit-box-align: end;
          align-items: flex-end;
  flex-wrap: wrap;
}

.outerContainer {
  width: 200px;
  margin: 1em;
}

.container {
  width: 200px;
  height: 200px;
  border: 1px solid #fff;
  border-radius: 4px;
  display: -webkit-box;
  display: flex;
  -webkit-box-align: center;
          align-items: center;
  -webkit-perspective: 240px;
          perspective: 240px;
}

.square {
  width: 100px;
  height: 100px;
  background-color: green;
  -webkit-transform: rotateY(90deg);
          transform: rotateY(90deg);
}

.containerA > .square {
  -webkit-animation: moveSquare 4s infinite ease-in-out alternate;
          animation: moveSquare 4s infinite ease-in-out alternate;
}

@-webkit-keyframes moveSquare {
  from {
    -webkit-transform: translateX(-100px) rotateY(90deg);
            transform: translateX(-100px) rotateY(90deg);
  }
  to {
    -webkit-transform: translateX(100px) rotateY(90deg);
            transform: translateX(100px) rotateY(90deg);
  }
}

@keyframes moveSquare {
  from {
    -webkit-transform: translateX(-100px) rotateY(90deg);
            transform: translateX(-100px) rotateY(90deg);
  }
  to {
    -webkit-transform: translateX(100px) rotateY(90deg);
            transform: translateX(100px) rotateY(90deg);
  }
}

.containerB {
  -webkit-animation: moveOrigin 4s infinite ease-in-out alternate;
          animation: moveOrigin 4s infinite ease-in-out alternate;
}

@-webkit-keyframes moveOrigin {
  from {
    -webkit-perspective-origin: left;
            perspective-origin: left;
  }
  to {
    -webkit-perspective-origin: right;
            perspective-origin: right;
  }
}

@keyframes moveOrigin {
  from {
    -webkit-perspective-origin: left;
            perspective-origin: left;
  }
  to {
    -webkit-perspective-origin: right;
            perspective-origin: right;
  }
}