Box is part of Coach. Box is related to Shape. 
Book can be used for School. Skull is etymologically related to School. Skull is related to Protection. Protection is a type of Security. 
Coach <--PartOf-- Box <--RelatedTo--> Shape 
Book --UsedFor--> School <--EtymologicallyRelatedTo-- Skull <--RelatedTo--> Protection --IsA--> Security 