     width: 4em;
      color: aqua;
      background: fuchsia;
    }

    .controlC {
      color: orange;
      background: orange;
      width: 2em;
      margin-left: -2em;
      border-left: 2em solid blue
    }

    .controlB {
      color: yellow;
    }
    .controlC {
      margin-left: 0;
    }
  ]]></style>

 </head>

 <body>

  <p>The patterns in the 2 silver boxes must be <strong>identical</strong>.</p>

  <div class="container">
    A&nbsp;&nbsp;<span class="controlB">B</span>
    <div class="co