Iron is a type of Element. Element is related to Silver. Silver is related to Valuable. 
Spin is a type of Stream. Stream can be used for Swimming. Swimming is a synonym of Swim. People wants (to) Swim. 
Iron --IsA--> Element <--RelatedTo--> Silver <--RelatedTo--> Valuable 
Spin --IsA--> Stream --UsedFor--> Swimming <--Synonym--> Swim <--Desires-- People 