<!DOCTYPE html>

<html>
<head>
  <style>
    .box {
      display: inline-block;
      height: 120px;
      width: 200px;
      margin: 10px;
      border: 1px solid black;
      background-repeat: no-repeat;
    }

    .linear1 {
      background-image: linear-gradient(to right, red -80%, -50%, green, blue, green, 150%, blue 170%);
    }

    .linear2 {
      background-image: linear-gradient(to right, red, 10%, green 100px, 60%, blue);
    }

    .linear3 {
      background-image: linear-gradient(to right, red, 10%, green, 60%, blue);
    }

    .linear4 {
      background-image: linear-gradient(to right, red 4em, 6em, green 10em, 11em, blue);
    }

    .linear5 {
      background-image: linear-gradient(to right, red 10px, 10%, green 50px, 60%, blue 100px);
    }

    .linear6 {
      background-image: linear-gradient(to right, red 5%, 100px, green 50%, 160px, blue 90%);
    }
  </style>
  <script type="text/javascript" charset="utf-8">
    if (window.testRunner) {
      var dumpPixels = true;
      testRunner.dumpAsText(dumpPixels);
    }
  </script>
</head>
<body>

  <div class="linear1 box"></div>
  <div class="linear2 box"></div>
  <div class="linear3 box"></div>
  <br>
  <div class="linear4 box"></div>
  <div class="linear5 box"></div>
  <div class="linear6 box"></div>

</body>
</html>