<table xmlns:m="http://xml.zope.org/namespaces/metal" m:define-macro="myTable">
<!-- macro definition with slots -->
  <tr>
    <td>Top Left</td>
    <td>Top Right</td>
  </tr>
  <tr>
    <td>Bottom left</td>
    <td><span m:define-slot="bottomRight">Bottom Right</span></td>
  </tr>
</table>