Small is related to Road. Road is related to Rest. 
Experiment is related to Study. Study is related to Course. Course is a different concept from Fine. Fine is a synonym of Thin. 
Small <--RelatedTo--> Road <--RelatedTo--> Rest 
Experiment <--RelatedTo--> Study <--RelatedTo--> Course <--DistinctFrom--> Fine <--Synonym--> Thin 