Lists of each different type may be nested inside of each other, creating complex lists for indexes, menus, etc.
Each subsequent level is a list item of the parent list, and is created as follows:
<OL> <LI> This is Item 1 of the main list <UL> <LI> This is Item 1 of the first level sub list <LI> This is Item 2 of the first level sub list </UL> <LI> This is Item 2 of the main list </OL>