Gun is related to Guard. Guard is a type of Watch. Watch is a type of Surveillance. 
Heart is a type of Pump. Heart is a synonym of Interior. Interior is similar to Inside. Inside is related to Possess. 
Gun <--RelatedTo--> Guard --IsA--> Watch --IsA--> Surveillance 
Pump <--IsA-- Heart <--Synonym--> Interior <--SimilarTo--> Inside <--RelatedTo--> Possess 