  </td>
            </tr>
            <tr>
                <td colspan="2">
                    <!-- controls -->
                    <div class="controls">
                        <button type="button" id="init" onclick="onInit()">Init/Reset</button>
                        <button type="button" id="step" onclick="onStep()">Step</button>
                    </div>
                    <div id="output" class="output"></div>
                </td>
            </tr>
            <tr>
                <td>
       