Scale is related to Instrument. Instrument is related to Drum. Drum is a synonym of Barrel. Butt is a type of Barrel. 
Interest is related to Debt. Debt is a different concept from Good. Good is related to Fellow. Fellow is related to Odd. 
Scale <--RelatedTo--> Instrument <--RelatedTo--> Drum <--Synonym--> Barrel <--IsA-- Butt 
Interest <--RelatedTo--> Debt <--DistinctFrom--> Good <--RelatedTo--> Fellow <--RelatedTo--> Odd 