Retain is a type of Remember. one thing you do when you Remember is Revelation. Revelation is derived from Reveal. 
Joke is similar to Comedy. Comedy is related to Entertainment. Entertainment is related to Radio. Radio is related to Communication. 
Retain --IsA--> Remember --HasSubevent--> Revelation --DerivedFrom--> Reveal 
Joke <--SimilarTo--> Comedy <--RelatedTo--> Entertainment <--RelatedTo--> Radio <--RelatedTo--> Communication 