
          <tr>
            <td style="font-family: Courier New,Courier,monospace;">voronoi_vertex_type*
            <span style="font-weight: bold;">vertex0</span>() </td>
            <td>Returns the pointer to the
start point of the edge.<br>
If the edge is infinite in that direction returns NULL. </td>
          </tr>
          <tr>
            <td style="font-family: Courier New,Courier,monospace;">const
voronoi_vertex_type* <span style="font-weight: bold;">vertex0</span>()
const </td>
            <td>R