Pork is related to Product. Corn is a type of Product. 
Law is related to Document. Form is a type of Document. Dish is a type of Form. Dish can be used for Cooking. 
Pork <--RelatedTo--> Product <--IsA-- Corn 
Law <--RelatedTo--> Document <--IsA-- Form <--IsA-- Dish --UsedFor--> Cooking 