Elevator is a type of Room. Elevator is related to Step. Step is a type of Supply. 
Crowd is related to Wave. Wave is related to Rise. Rise is a synonym of Hike. 
Room <--IsA-- Elevator <--RelatedTo--> Step --IsA--> Supply 
Crowd <--RelatedTo--> Wave <--RelatedTo--> Rise <--Synonym--> Hike 