Forehead is related to Part. Part is related to Bar. Bolt is a type of Bar. Bolt is related to Mechanical. 
Attack is related to Army. Army is related to Tank. 
Forehead <--RelatedTo--> Part <--RelatedTo--> Bar <--IsA-- Bolt <--RelatedTo--> Mechanical 
Attack <--RelatedTo--> Army <--RelatedTo--> Tank 