polygon()

clip-path: polygon(
  0% 20%,
  60% 20%,
  60% 0%,
  100% 50%,
  60% 100%,
  60% 80%,
  0% 80%
);

clip-path: polygon(50% 0%, 100% 50%, 50% 100%, 0% 50%);

<section class="default-example" id="default-example">
  <div class="transition-all" id="example-element"></div>
</section>

#default-example {
  background: #fe9;
}

#example-element {
  background: linear-gradient(to bottom right, #f52, #05f);
  width: 100%;
  height: 100%;
}

/* 指定坐标列表 */
/* polygon(<length-percentage> <length-percentage>, ... )*/
polygon(50% 2.4%, 34.5% 33.8%, 0% 38.8%, 25% 63.1%, 19.1% 97.6%)
polygon(0px 0px, 200px 100px, 0px 200px)
polygon(0% 0px, 100% 100px, 0px 100%)
polygon(0 0, 50% 1rem, 100% 2vw, calc(100% - 20px) 100%, 0 100%)

/* 指定填充规则和坐标列表 */
/* polygon(<fill-rule> <length-percentage> <length-percentage>, ... )*/
polygon(nonzero, 0% 0%, 50% 50%, 0% 100%)
polygon(evenodd, 0% 0%, 50% 50%, 0% 100%)

clip-path: polygon(0% 0%, 100% 0%, 100% 100%, 0% 100%);

<div class="triangle"></div>

.triangle {
  width: 400px;
  height: 400px;
  background-color: magenta;
  clip-path: polygon(100% 0%, 50% 50%, 100% 100%);
}

<div class="box">
  <div class="shape"></div>
  <p>
    据说，1782 年 11
    月的一个夜晚，在法国小城安诺内，有两兄弟坐在冬日的炉火旁，看着炉膛里灰色的烟圈沿着宽大的烟囱袅袅升起。他们的名字叫斯蒂芬·蒙哥菲尔和约瑟夫·蒙哥菲尔，职业是造纸工人，以心思缜密著称，对所有科学知识和新发现都有着浓厚的兴趣。在那个夜晚——一个值得纪念的夜晚——之前，数以亿计的人都在注视着自家炉火升起的烟圈，却没有从中得到任何特别的启发。
  </p>
</div>

.box {
  width: 250px;
}

.shape {
  float: left;
  shape-outside: polygon(
    0 5%,
    15% 12%,
    30% 15%,
    40% 26%,
    45% 35%,
    45% 45%,
    40% 55%,
    10% 90%,
    10% 98%,
    8% 100%,
    0 100%
  );
  width: 300px;
  height: 320px;
}

p {
  font-size: 0.9rem;
}