Task Tree is easy to use task manager supports 'tree structured' tasks.
'A tree structure is a way of representing the hierarchical nature of a structure in a graphical form. It is named a "tree structure" because the classic representation resembles a tree, even though the chart is generally upside down compared to an actual tree, with the "root" at the top and the "leaves" at the bottom.' - Wikipedia :: Tree Structure
- Easy to use.
- Automatically update progress status of sub tasks.
- iCloud backup and restore.
- Can create unlimited depth of subcategories.