How can I create a bifurcation-like mesh easily using Grasshopper?

Hi everyone,

I want to create lots of bifurcation-like meshes, as the pic shows. My idea is to create three meshes separately, then join the meshes together. However, how can I realized it in GH?
Any idea or suggestion is appreciated! (811 Bytes)

The mesh wasn’t internalised. Would this work for you? (8.1 KB)

Thank you, ME_Mark!
I think this mesh is not what I asked. I will try following you idea.
Sorry I forgot to internalise the mesh. Here is the new file. (2.4 KB)