Luck is a type of Phenomenon. Stress is a type of Phenomenon. Stress is related to Work. 
Pop is a type of Fire. Pop is related to Music. Music is related to Kind. Kind is related to Generous. 
Luck --IsA--> Phenomenon <--IsA-- Stress <--RelatedTo--> Work 
Fire <--IsA-- Pop <--RelatedTo--> Music <--RelatedTo--> Kind <--RelatedTo--> Generous 