I'd like to be able to create a highlight that can link two or more items together. Cause / Effect would be a common usage but could be other things like lists, contrast, etc.
There are probably a number of ways you could expose this. I can loosely associate by highlighting my first piece, then opening the note and adding an anchor for the second piece. That at least gives them a common highlight, but there's no other visual connection or description of the relationship.
It would be interesting if I could describe the relationship (this piece is cause, this piece effect), hover over one side of the highlight, for instance, and it would show a connecting line to the other location (using a popup if necessary to highlight something offscreen / in another resource even) along with the descriptive relationship. A common way I've seen this done in graph-based editors is the ability to add a description to the connecting line itself (like in cause/effect, I might label it "causes" where x ——causes—→ y).
