Sidewalk is a synonym of Platform. Platform is related to Bed. Bed is related to Sand. Sand is related to Ground. 
Spill is a synonym of Fall. Fall is related to Accident. Accident is a synonym of Condition. Nomination is a type of Condition. 
Sidewalk <--Synonym--> Platform <--RelatedTo--> Bed <--RelatedTo--> Sand <--RelatedTo--> Ground 
Spill <--Synonym--> Fall <--RelatedTo--> Accident <--Synonym--> Condition <--IsA-- Nomination 