Poem is related to Song. Song is related to Part. Part is related to Stair. 
you are likely to find Scary in/at/on Bed. Bed is related to River. River can be used for Swimming. 
Poem <--RelatedTo--> Song <--RelatedTo--> Part <--RelatedTo--> Stair 
Scary --AtLocation--> Bed <--RelatedTo--> River --UsedFor--> Swimming 