Random is a synonym of Speed. Speed is related to Fast. Fast is related to Flash. Flash is related to Memory. 
Accident is etymologically related to Case. Portfolio is a type of Case. 
Random <--Synonym--> Speed <--RelatedTo--> Fast <--RelatedTo--> Flash <--RelatedTo--> Memory 
Accident --EtymologicallyRelatedTo--> Case <--IsA-- Portfolio 