Rebel is related to Protest. Protest is related to Anger. Anger is related to Disappointment. Disappointment is related to Fail. 
Elbow is a type of Pipe. Elbow is related to Bend. 
Rebel <--RelatedTo--> Protest <--RelatedTo--> Anger <--RelatedTo--> Disappointment <--RelatedTo--> Fail 
Pipe <--IsA-- Elbow <--RelatedTo--> Bend 