Guard is related to Block. Block is related to Wooden. Wooden is the opposite of Metal. Metal is related to Category. 
Math is related to Division. Division is related to Type. Type is related to Servant. 
Guard <--RelatedTo--> Block <--RelatedTo--> Wooden <--Antonym--> Metal <--RelatedTo--> Category 
Math <--RelatedTo--> Division <--RelatedTo--> Type <--RelatedTo--> Servant 