Help with visualizing a chain of relationships

I wonder if I can interest anyone skilled in d3 into making visualization of relationship paths. Basically it’s a chain of connections that can go up one step, go to the right one step, or go down one step. As long as we stick with a single path between two individuals, it should be well-defined.

Here’s an example (not a terribly good one, I apologize)

Thanks in advance!

You can already find several examples of genealogy/family trees built with d3 on the web (and even libraries), e.g.:

Is there anything in particular that you have trouble implementing?

I’ve done a family tree, built on the collapsible tree in d3 (not that I understood the code). I thought maybe someone would have other ideas how to present the path (not really a tree) on the screen.