On the right you may see a demo of a dependency graph. It contains around 170 nodes with some of the nodes being arranged into multiple explicit sequences that show the evolution and order of dependency of said nodes. We need to display all of the node sequences together in one hierarchy meanwhile allowing the user to see the seperate individual sequences and their nodes. In order to accomplish this, we can set priority for how nodes should align under their parents. In a family diagram every node may have multiple parents and by default aligns itself to be equally distanced from all of them. In this case however, we are intrested in having nodes be closer or farther away from a specific parent. This is done by giving higher priority to one of its parents. Our family diagram provides the property primaryParent which can be applied to a node. Automatically indicating that the child node or nodes should be alligned closer to said parent within the hierarchy. This property is optional and doesn't change any node relations, so if it is applied to a non-exsisting parent then it will simply be ignored.
This alignment priority can then be used to create a full sequence, branch or chain of nodes within a grander herarchy. This can be seen if you take a look at the sequence of flight related technologies starting from "Subsonic flight" and ending with "Cutting-Edge Aeronautics".
In the diagram red connection annotations display "primaryParent" references to enforce the hierarchy and blue annotations display references enforcing the sorting of nodes within one group.