<div class="container">
    <div class="obj" style="width: 10vw; height: 3vw; top: 5vw;"></div>
    <div class="obj" style="width: 3vw; height: 10vw; left: 1vw; clip: rect(0,2vw,10vw,0);"></div>
</div>
<style>
    .container {
        position: relative;
        margin: 1vw;
    }
    .obj {
        position: absolute;
        background-color: rgba(0,0,0,.6);
    }
</style>