<css-doodle>
  <style>
    @grid: 20 / 60vmin;

    background: cyan;
    scale: 0;
    opacity: 0;
    animation: m 4s linear infinite;
    
    animation-delay: calc(
      -1s/@I * @i * @sin(@i)
    );

    @keyframes m {
      0%, 50%, 90% { scale: 1; opacity: 1 }
      25%, 75%, 100% { scale: 0; opacity: 0 }
    }
  </style>
 </css-doodle>

html, body {
  padding: 0;
  height: 100%;
  display: grid;
  place-content: center;
  background: #0A0A27;
}