Hasta La Motion!

I seem to remember being able to do this in Shake, but I can’t find the correct script/expression for it in Nuke.

What I would like to do is be able to write an expression into a node that reads directly the number associated with that node.
For example, I would like to be able to create a sphere (Sphere1) with a universal scale of 1, and then copy and paste it, creating another sphere (Sphere2), which automatically updates itself to have a univeral scale of 2.
I feel like there should be a simple expression that can do this without me having to resort to scripting it in Python, but maybe not.
Any ideas?
Many thanks…