chromium/third_party/blink/web_tests/fast/borders/borderRadiusDotted06.html

<style>
    #t {
        width: 400px;
        height: 400px;
        border: 20px dotted rgba(255,0,0,1);
        border-radius: 200px / 100px;
        border-left-color: rgba(0,0,255,1);
        border-bottom-color: rgba(0,128,0,0.5);
        border-right-color: rgba(0,128,0,0.5);
        -moz-box-sizing: border-box;
        box-sizing: border-box;
        margin: 20px;
    }
    div {
        margin: 10px 0;
    }
  </style>
  <div id="t"></div>