<!DOCTYPE html>
<html>
  <head>
    <style>
      table {
        margin: 0;
        padding: 0;
        width: 25px;
        height: 50px;
        border-collapse: collapse;
      }
      td {
        margin: 0;
        padding: 0;
      }
      #rel {
        position: relative;
        margin: 0;
        padding: 0;
      }
      #abs {
        position: absolute;
        margin: 0;
        padding: 0;
        bottom: 25px;
        right: 25px;
        width: 50px;
        height: 50px;
        background-color: green;
      }
      #bottomright {
        position: absolute;
        margin: 0;
        padding: 0;
        bottom: 0;
        right: 0;
        width: 50px;
        height: 50px;
        overflow: visible;
        background-color: blue;
      }
    </style>
  </head>
  <body>
    The green square should not overlap the blue square.
    <div id="bottomright">
      <table>
        <colgroup>
          <col style="width: 20%">
          <col>
        </colgroup>
        <thead id="rel">
          <tr>
            <td></td>
            <td></td>
          </tr>
          <tr>
            <td>
              <div id="abs"></div>
            </td>
            <td></td>
          </tr>
        </thead>
      </table>
    </div>
  </body>
</html>