<style>
  * {
    box-sizing: border-box;
  }
  html, body {
    align-items: center;
    background: linear-gradient(45deg, #9a12b3, #4ecdc4);
    display: flex;
    justify-content: center;
    margin: 0;
    min-height: 100vh;
    padding: 0;
    width: 100vw;
  }
  div {
    background-color: #fff;
    border-radius: 100%;
    height: 100px;
    transform: translate(-100%, -100%);
    width: 100px;
  }
</style>
<div></div>
div {
  animation-name: squarePath;
  animation-duration: 2s;
}

@keyframes squarePath {
  0%, 100% {
    transform: translate(-100%, -100%);
  }
  25% {
    transform: translate(100%, -100%);
  }
  50% {
    transform: translate(100%, 100%);
  }
  75% {
    transform: translate(-100%, 100%);
  }
}

External CSS

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External JavaScript

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