Eye can be used for Learning. Eye is a type of Organ. Organ is related to Musical. Musical is related to Tune. 
Circuit is related to Electric. Electric is related to Spark. 
Learning <--UsedFor-- Eye --IsA--> Organ <--RelatedTo--> Musical <--RelatedTo--> Tune 
Circuit <--RelatedTo--> Electric <--RelatedTo--> Spark 