Full Idea
If both the statue and the clay fall on someone and crush them to death, we would not say that the death is overdetermined.
Gist of Idea
If statue and clay fall and crush someone, the event is not overdetermined
Source
S.Mumford/R.Lill Anjum (Getting Causes from Powers [2011], 2.7)
Book Reference
Anjum,R.J./Mumford,S.: 'Getting Causes from Powers' [OUP 2011], p.43
A Reaction
I don't need many reasons to give up the idea that the statue and the clay are two objects, but this will do nicely as one of them.