I don't know how to model a bifurcated path.
I'd like to do something good instead of that is bad bifurcation at 2 seconds of this video (the pipe is not full: it doesn't follow the full path at the bifurcation)
blender file of this video: https://drive.google.com/file/d/1M-8bKI7HsQxkfTsXez3lHQMdFCpU40yR/view?usp=sharing
Thank you for these links showing how to fork a path. But even with this fork created, the pipe does not follow it. A solution?