#### Nodes Reachable

The collection of "Nodes Reachable" from a particular Part contains all (and only) those Nodes that can be reached by following the following a path of Links. For example, Node D is reachable from Node A, since one can reach D from A via Links A --> C and C --> D. Node A, however, is not reachable from Node D.

The logic to highlight the appropriate Nodes is in the RecursiveTo method. It will set the data's Highlight property to increasing values as the nodes are "farther away" in terms of relationships, not in terms of Cartesian distance.