Bill is related to Duck. Duck is related to Small. Small is related to Car. Car is related to Auto. 
Fighter is related to Soldier. Soldier can be used for Guard. Guard is a synonym of Defend. Defend is a synonym of Fence. 
Bill <--RelatedTo--> Duck <--RelatedTo--> Small <--RelatedTo--> Car <--RelatedTo--> Auto 
Fighter <--RelatedTo--> Soldier --UsedFor--> Guard <--Synonym--> Defend <--Synonym--> Fence 