Welcome is related to Thanks. Thanks is a form of Thank. you would Thank because Appreciate. 
Mud is a type of Dirt. Mud is related to Chocolate. you are likely to find Chocolate in/at/on Mouth. Mouth is related to Bill. 
Welcome <--RelatedTo--> Thanks --FormOf--> Thank --MotivatedByGoal--> Appreciate 
Dirt <--IsA-- Mud <--RelatedTo--> Chocolate --AtLocation--> Mouth <--RelatedTo--> Bill 