CSS Animatable grid-auto-flow Property Example

<!DOCTYPE html>
<html>
<head>
<style> 
#grid-container {
    display: grid;
    grid-template-columns: auto auto auto;
    grid-template-rows: auto auto;
    grid-auto-flow: row;
    background: #333;
    grid-gap: 5px;
    padding: 5px;
	box-shadow: 0 0 10px 0 #aaa;
    animation: anim 5s infinite;
}
  
#grid-container div {
    text-align: center;
    padding: 20px 0;
    font-size: 20px;
    background: #97ff99;
}

@keyframes anim { 
    50% {grid-auto-flow: column;}
}
</style>
</head>
<body>

<h1>Animatable 'grid-auto-flow' Property</h1>
<hr>
  
<p>Experience the changing grid-auto-flow from rows to columns.</p>

<div id="grid-container">
    <div class="item1">1</div>
    <div class="item2">2</div>
    <div class="item3">3</div>  
    <div class="item4">4</div> 
</div>

</body>
</html>