  .container .animation { width: 400px; }
    .container .controls { width: 200px; }
    .container .graph { width: 640px; }
  </style>
</head>
<body>
  <h1>Ring oscillator demo</h1>

  <div class="container">
    <div class="animation">
      <canvas id="canvas" width=400 height=400></canvas>
    </div>
    <div class="controls">
      <input id="go" type="button" style="background-image: url(play-icon.png); width: 20px;" value="">
      <input id="stop" type="button" style="background-image: url(stop-icon