Relative is related to Uncle. Uncle is a type of Male. Male is related to Policeman. Inspector is a type of Policeman. 
Line can be used for Trace. Line is a synonym of Tune. Signature is a type of Tune. Signature is related to Writing. 
Relative <--RelatedTo--> Uncle --IsA--> Male <--RelatedTo--> Policeman <--IsA-- Inspector 
Trace <--UsedFor-- Line <--Synonym--> Tune <--IsA-- Signature <--RelatedTo--> Writing 