Positive is related to Metal. Metal is a different concept from Plastic. 
Nest is related to Pile. Pile is related to File. Index is a type of File. Index is a synonym of Indicator. 
Positive <--RelatedTo--> Metal <--DistinctFrom--> Plastic 
Nest <--RelatedTo--> Pile <--RelatedTo--> File <--IsA-- Index <--Synonym--> Indicator 