Treemaps will be great way to arrange data.
No duplicates are allowed in treemaps.
Treemap nodes will be referred usually with text.
Each node may have children or be leaf (no children).
Each node may have parent or be root(no parent).
Each treemap must have one root.
Treemaps nodes do not store additional data. To store data, you may run parallel hashtable or nested list or even hash-nested list.

Blocks used (exclude red blocks):

Add treemap [ v] to [] in treemap [ v] :: list
Remove treemap ( v) at [] in treemap [ v] :: list
Set treemap [ v] to sub-treemap at node [] in treemap [ v] :: list
reporter (parent of node [] in treemap [ v] :: list)
reporter (child count of node [] in treemap [ v] :: list)
reporter (child #() of node [] in treemap [ v] :: list)
predicate <treemap [ v] contains [thing] ? :: list>
Make [] as child of [] in [ v] :: list
Set list [ v] to all children of [] in [ v] :: list

Uses with hashtables:
References to nested lists
Value hierarchy

Uses with hash-nested lists
List hierarchy