<svg version="1.0" viewBox="0 0 400 300" width="400" height="300"
     xmlns="http://www.w3.org/2000/svg">
  <defs>
     <style type="text/css">
        text {
            font-size:12px;
            text-anchor:middle;
            font-family:Bitstream Vera Sans;
            text-align:center;
            font-weight:normal;
            font-style:normal;
            fill:#000000;
        }
        .label { font-size:16px; font-weight: bold; }
        ellipse { stroke:#000; fill-opacity:0.8; }
     </style>
  </defs>
  <ellipse cx="125" cy="110" rx="100" ry="65" fill="#66d" />
  <ellipse cx="270" cy="180" rx="100" ry="65" fill="#6d6" />
  <text class="label" x="85" y="30">Perl</text>
  <text class="label" x="325" y="110">SVG</text>
  <text x="125" y="100">Collect data</text>
  <text x="125" y="116">Respond to requests</text>
  <text x="270" y="170">Display instruments</text>
  <text x="270" y="186">Request data</text>
  <text x="270" y="202">Update instruments</text>
</svg>
