Politician is related to Person. Person is related to Personality. 
Level is related to Edge. Edge is related to Margin. Margin is related to Book. you are likely to find Poem in/at/on Book. 
Politician <--RelatedTo--> Person <--RelatedTo--> Personality 
Level <--RelatedTo--> Edge <--RelatedTo--> Margin <--RelatedTo--> Book <--AtLocation-- Poem 