Hand is related to Extension. Extension is a type of Telephone. 
Pool is a type of Group. Pool is a type of Stake. Stake is a synonym of Pole. Boom is a type of Pole. 
Hand <--RelatedTo--> Extension --IsA--> Telephone 
Group <--IsA-- Pool --IsA--> Stake <--Synonym--> Pole <--IsA-- Boom 