Idea is a type of Content. Goal is a type of Content. Goal is related to Prove. Prove is related to True. 
Trip is related to Summer. Summer is related to Beach. Beach is related to Tide. 
Idea --IsA--> Content <--IsA-- Goal <--RelatedTo--> Prove <--RelatedTo--> True 
Trip <--RelatedTo--> Summer <--RelatedTo--> Beach <--RelatedTo--> Tide 