LayoutTests/animations/additive-transform-animations.html

<style>
    #original {
        position: absolute;
        top: 100px;
        left: 100px;
        width: 100px;
        height: 100px;
        background-color: blue;
    }

    #rotator {
        position: absolute;
        top: 100px;
        left: 100px;
        width: 100px;
        height: 100px;
        background-color: red;
        animation: animation 5s infinite linear;
    }

    #cover {
        position: absolute;
        top: 150px;
        left: 50px;
        width: 200px;
        height: 150px;
        background-color: green;
    }

    @keyframes animation {
        from { transform: rotate(40deg) translate(50%, 50%) }
        to { transform: rotate(60deg) translate(50%, 50%) }
    }
</style>
<p>You should not see any of the rotating red rectangle</p>
<div id="original"></div>
<div id="rotator"></div>
<div id="cover"></div>