public class Menu
{
    public string Title;
    public List<Menu> Items;
}

<menu title='File'>
  <items>
    <menu title='Open'/>
    <menu title='Options'>
       <items>
          <menu title='Edit'/>
       </items>

     /menu>
   </items>
</menu>

H0 = 1
H1 = 2 * x
Hn+1(x) = 2 * x * Hn(x) - 2 * n * Hn-1(x)