Rifle is related to Barrel. Barrel is related to Wood. Wood is related to Bed. Bed is related to Night. 
Proof is a type of Evidence. Demonstration is a type of Proof. 
Rifle <--RelatedTo--> Barrel <--RelatedTo--> Wood <--RelatedTo--> Bed <--RelatedTo--> Night 
Evidence <--IsA-- Proof <--IsA-- Demonstration 