JSFiddle - React, Tailwind, and code Playground

HTML

<div class="test"></div>

CSS

.test {
  position: relative;
  background-color: #333;
  width: 500px;
  height: 3em;
  overflow: hidden;
}

.test::before {
  content: "";
  position: absolute;
  top: 50%;
  left: 0;
  transform: translate(-50%,-50%) rotate(45deg);
  overflow: hidden;
  width: 2.121em;
  height: 2.121em;
  background-color: #c00;
  mix-blend-mode: color-dodge;
}
.test::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 100%;
  transform: translate(-50%,-50%) rotate(45deg);
  overflow: hidden;
  width: 2.121em;
  height: 2.121em;
  background-color: #c00;
  mix-blend-mode: color-dodge;
}