Carrot is related to Stick. Stick is related to Pool. Pool is related to Place. Place is related to Happen. 
Physician is a synonym of Doctor. Doctor is related to Psychology. 
Carrot <--RelatedTo--> Stick <--RelatedTo--> Pool <--RelatedTo--> Place <--RelatedTo--> Happen 
Physician <--Synonym--> Doctor <--RelatedTo--> Psychology 