I'm working on a sequence diagram for a layered system that has a tree hierarchy. Now I have a process that works itself recursively down the tree. Meaning calling the same function on a child object. I'm talking about a tree like this: -layer n -layer n-1 -layer n-2 -... -layer n-2 -... -layer n-1 -layer n-2 -... -layer n-2 -... Its easy to visualize a recursive process in the single object, but I could figure out how I would visualize recursive process that recursively calls itself on a lower layer object and so on. Is this even possible with an UML sequence diagram?