Assign is a type of Judge. Judge requires Observe. 
Smoke requires Quit. Smoke is a type of Indication. Trace is a type of Indication. Trace is related to Drawing. 
Assign --IsA--> Judge --HasPrerequisite--> Observe 
Quit <--HasPrerequisite-- Smoke --IsA--> Indication <--IsA-- Trace <--RelatedTo--> Drawing 