<hexagon>
  <radius>2</radius>
  <filledTriangles>
    <triangle>
      <I>1</I>
      <J>2</J>
    </triangle>
    <triangle>
      <I>1</I>
      <J>4</J>
    </triangle>
    <triangle>
      <I>2</I>
      <J>3</J>
    </triangle>
  </filledTriangles>
</hexagon>