p {
  width: 50px;
}

.some-float {
    display: block;
    width: 80px;
    height: 1px;
    position: relative;
    float: left;
    shape-outside: polygon(0 0, 100% 0);
}

<div class="some-float"></div>
<p> <span>Hello</span> <span>World</span> </p>