What is the name of the knowledge visualisation that shows independent paths which occasionally converge at certain points? (photo inside)

If I had Data that looked like this:

Path 1 - Green, Yellow, Orange
Path 2 - Green, Purple, Blue, Maroon 
Path 3 - Green, Blue, Maroon, Red
Path 4 - Green, Cyan, Grey, Magenta

It could be visualized to look like this:

Each path could be a particular learning journey (degree, certification, etc) and each color could be a topic that must be learned in persuit of that learning journey. Multiple learning journies can touch on the same concepts, but still have their own unique full path.

I tried to search online, but I couldn't remember the term for this type of illustration. It's not Swimlames, it's not a mindmap, it's not a decision tree, it's not quite a sankey diagram, etc...

What is the name of this type of data visualization?

(Bonus Points if you know of a piece of software or webapp that creates these).

Thank you.