Vary is a synonym of Depart. Depart is a synonym of Die. Die is related to Action. Action is related to Cook. 
Bat is related to Thing. Thing is related to Machine. Rocket is a type of Machine. 
Vary <--Synonym--> Depart <--Synonym--> Die <--RelatedTo--> Action <--RelatedTo--> Cook 
Bat <--RelatedTo--> Thing <--RelatedTo--> Machine <--IsA-- Rocket 