Farmer is related to Animal. Animal is related to Pig. Pig is related to Girl. 
Fire is related to Stove. Stove is related to Cooking. Cooking is related to Herb. Herb is related to Natural. 
Farmer <--RelatedTo--> Animal <--RelatedTo--> Pig <--RelatedTo--> Girl 
Fire <--RelatedTo--> Stove <--RelatedTo--> Cooking <--RelatedTo--> Herb <--RelatedTo--> Natural 