This play on words is known as a 'Tom Swifty'. It is a type of pun (joke) that plays on the relationship between the adverb and an action spoken in the dialogue. The sentence is usually in reported speech. Tom Swifty is a character who appears in a series of adventure stories written by the author Edward Stratemeyer. The pun in this case is on the adverb 'abstractly' as modern art is sometimes abstract.
