:doodle { @grid: 15 / 100%; } animation-name: bouncing; animation-iteration-count: infinite; animation-duration: 5s; animation-delay: calc(@rand(-5s, -1s, .1)); animation-timing-function: cubic-bezier(.70, .1, 1, 1); background: @pick( magenta, orange, cyan, red ); transform: translate( @rand(-40vw, 40vw), @rand(-40vh, 40vh) ); @size: 5vmin; @shape: heart; @place-cell: 50% 50%; @keyframes bouncing { 0% { opacity: 0; } 50% { opacity: 1; } 100% { transform: translate(0, 0); } }